Bounce Classification Codes and Definitions

Created by Stefan Perchinkov, Modified on Tue, 25 Feb at 6:28 AM by Stefan Perchinkov

Email Bounce Classification is a powerful tool designed to help businesses monitor, classify, and resolve email delivery issues. By identifying the causes of bounced emails, it empowers users to optimize their email campaigns for better deliverability. This article will guide you through the key features, benefits, and steps to effectively use the Email Bounce Classification feature to ensure emails reach your recipients' inboxes.

Key Features and Benefits:

  • Bounce Summary Overview: This feature provides detailed metrics on total permanent bounces, bounce rate, ESP/ISP blocks, and delivery rates, allowing you to assess email performance.
  • Detailed Bounce Classification: Breaks down bounces by the email service provider (e.g., Gmail, Google Workspace, Apple), bounce category (Mailbox Full, DMARC, Sender Reputation, Internal Errors, etc.), and status/error codes, offering precise insights into delivery failures.
  • ESP/ISP Block Tracking: Tracks blocks by email providers like Outlook or Google Workspace due to policy violations or spam-related issues, helping users take action with external troubleshooting links.
  • Advanced Filters: Refine reports using filters like sending domain, email service provider, email type, or sending IP to drill down on specific issues.
  • Actionable Troubleshooting: Provides direct links and guidance to resolve bounce issues like blacklist problems or misconfigured DNS records, improving email deliverability.

How to Use the Email Bounce Classification Feature:

  1. Access the Dashboard:
    Navigate to Settings > email services module within Referins. Look for the "Bounce Classification" section to access a comprehensive overview of your email bounces.
  1. Review Metrics: Examine key metrics such as total permanent bounces, delivery rates, and bounce rates to understand your overall email performance.
  2. Use Filters: Refine your report using advanced filters, such as selecting specific sending domains, email service providers, or error types to narrow down the exact causes of delivery issues.
  1. Analyze Bounce Details: Delve into specific bounce classifications, reviewing error codes, status codes, and categories like DMARC failures or mailbox-related issues. Each category will include a definition and potential resolution tips.
  2. Resolve Issues: Follow the actionable guidance provided with each bounce reason. For instance, if there is a DNS issue, the system will link you to resources for correcting SPF/DKIM/DMARC records or for resolving blacklist problems.
  3. Monitor Blocks: Pay attention to ESP/ISP blocks by providers like Outlook or Gmail, and use the links provided to troubleshoot and unblock IPs or domains if necessary.

Below is a detailed breakdown of these codes, covering the causes of the issues and practical solutions to resolve them effectively. Use this guide to quickly identify and fix any delivery problems you may encounter.

Blocked

Category
Code
Enhanced Code
Definition
Blocked
554
5.2.3
Your email was blocked because there's a policy or rule in place that's preventing the email from being delivered. This could be related to mailbox quotas, email size limits, or specific policies configured by the organization

DMARC
The message failed DMARC authentication because the "From" header does not align with the domains verified by SPF/DKIM.

Resolution Tips:

  • Ensure the "From" address aligns with the sending domain.
  • Confirm that SPF and DKIM are properly set up for the sending domain.
Category
Code
Enhanced Code
Definition
DMARC
509
5.7.509
The message was rejected by the recipient'semail provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.0.0
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.20
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.26
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.5
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.5
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.509
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.6
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.8
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
5.7.9
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
550
Missing
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
553
-
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
554
5.0.0
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
554
5.7.5
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.
DMARC
555
5.7.5
The message was rejected by the recipient's email provider because it did not pass the DMARC. Ensure that the "From" header domain matches or aligns with the SPF/DKIM-validated domains.

Invalid Address
This means you tried to send a message to a non-existent email address. The recipient may have entered an incorrect address or made a typo.

Resolution Tips:

  • Use Email Validation to verify email addresses before sending.
Category
Code
Enhanced Code
Definition
Invalid address
450
4.1.1
The recipient's email address is invalid or does not exist.
Invalid address
500
5.0.0
The recipient's email address is invalid or does not exist.
Invalid address
500
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
501
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
501
5.1.3
The recipient's email address is invalid or does not exist.
Invalid address
501
5.1.3
The recipient's email address is invalid or does not exist.
Invalid address
501
5.5.4
The recipient's email address is invalid or does not exist.
Invalid address
501
5.7.0
The recipient's email address is invalid or does not exist.
Invalid address
505
-
The recipient's email address is invalid or does not exist.
Invalid address
508
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
511
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
511
-
The recipient's email address is invalid or does not exist.
Invalid address
521
5.3.2
The recipient's email address is invalid or does not exist.
Invalid address
522
5.7.1
The recipient's email address is invalid or does not exist.
Invalid address
525
5.7.13
The recipient's email address is invalid or does not exist.
Invalid address
540
5.7.1
The recipient's email address is invalid or does not exist.
Invalid address
542
-
The recipient's email address is invalid or does not exist.
Invalid address
550
5.0.0
The recipient's email address is invalid or does not exist.
Invalid address
550
5.0.0
The recipient's email address is invalid or does not exist.
Invalid address
550
5.0.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.0.350
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.0
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.10
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.10
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.181
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.2
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.2
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.351
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.351
The recipient's email address is invalid or does not exist.
Invalid address
550
5.1.6
The recipient's email address is invalid or does not exist.
Invalid address
550
5.2.1
The email account that you tried to reach is inactive.
Invalid address
550
5.2.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.2.14
The recipient's email address is invalid or does not exist.
Invalid address
550
5.2.5
The recipient's email address is invalid or does not exist.
Invalid address
550
5.3.0
The recipient's email address is invalid or does not exist.
Invalid address
550
5.3.2
The recipient's email address is invalid or does not exist.
Invalid address
550
5.3.2
The recipient's email address is invalid or does not exist.
Invalid address
550
5.4.310
The recipient's email address is invalid or does not exist.
Invalid address
550
5.4.312
The recipient's email address is invalid or does not exist.
Invalid address
550
5.4.350
The recipient's email address is invalid or does not exist.
Invalid address
550
5.4.355
The recipient's email address is invalid or does not exist.
Invalid address
550
5.5.0
The recipient's email address is invalid or does not exist.
Invalid address
550
5.5.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.5.2
The recipient's email address is invalid or does not exist.
Invalid address
550
5.7.0
The recipient's email address is invalid or does not exist.
Invalid address
550
5.7.1
The recipient's email address is invalid or does not exist.
Invalid address
550
5.7.100
The recipient's email address is invalid or does not exist.
Invalid address
550
5.7.13
The recipient's email address is invalid or does not exist.
Invalid address
550
5.8.1
The recipient's email address is invalid or does not exist.
Invalid address
550
-
The recipient's email address is invalid or does not exist.
Invalid address
550
-
The recipient's email address is either invalid or does not exist and is already on the bounce list. Please revalidate the email address and try again.
Invalid address
550
-
The recipient's email address is invalid or does not exist.
Invalid address
550
-
These errors are originating from the recipient's end due to a misconfiguration or an outage on their MX server.
Invalid address
551
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
551
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
551
-
The recipient's email address is invalid or does not exist.
Invalid address
552
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
553
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
553
5.1.3
The recipient's email address is invalid or does not exist.
Invalid address
553
5.3.0
The recipient's email address is invalid or does not exist.
Invalid address
553
5.3.0
The recipient's email address is invalid or does not exist.
Invalid address
553
5.5.3
The recipient's email address is invalid or does not exist.
Invalid address
553
5.7.1
The recipient's email address is invalid or does not exist.
Invalid address
553
5.7.2
The recipient's email address is invalid or does not exist.
Invalid address
554
5.0.0
The recipient's email address is invalid or does not exist.
Invalid address
554
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
554
5.1.2
The recipient's email address is invalid or does not exist.
Invalid address
554
5.2.1
The recipient's email address is invalid or does not exist.
Invalid address
554
5.2.2
The recipient's email address is invalid or does not exist.
Invalid address
554
5.5.1
The recipient's email address is invalid or does not exist.
Invalid address
554
5.7.1
The recipient's email address is invalid or does not exist.
Invalid address
554
5.7.7
The recipient's email address is invalid or does not exist.
Invalid address
554
-
The recipient's email address is invalid or does not exist.
Invalid address
556
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
572
-
The recipient's email address is invalid or does not exist.
Invalid address
577
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
585
5.1.1
The recipient's email address is invalid or does not exist.
Invalid address
605
-
The recipient's email address is already on the bounce list. Please revalidate the email address and try again.
Invalid address
612
-
These errors are originating from the recipient's end due to a misconfiguration or an outage on their MX server.

Mailbox
This error suggests that the email address you attempted to send a message to does not have an active mailbox.

Resolution Tips:

  • Verify email addresses using Email Validation before sending messages.
Category
Code
Enhanced Code
Definition
Mailbox
450
4.2.2
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
452
-
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
498
-
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
511
-
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
516
5.1.6
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
522
5.2.2
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
4.2.2
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
5.0.350
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
5.2.0
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
5.2.2
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
5.4.6
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
5.5.0
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
550
5.5.1
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
552
5.1.1
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
552
5.2.1
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
552
5.5.2
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
552
-
The recipient's domain has no mailbox and does not accept mail. Please send it to a valid email address.
Mailbox
553
5.3.1
The recipient's domain has no mailbox and does not accept mail. Please send to valid email address.
Mailbox
554
5.1.1
The recipient's domain has no mailbox and does not accept mail. Please send to valid email address.

Mailbox Full

A "Mailbox Full" bounce happens when the recipient's inbox has reached its storage capacity and is unable to receive new messages. This is typically a temporary issue, and emails can be delivered once the recipient clears space or increases their mailbox size.

Category
Code
Enhanced Code
Definition
Mailbox Full
452
4.1.1
The recipient's mailbox is full and cannot accept new emails.
Mailbox Full
452
4.2.2
The recipient's mailbox is full and cannot accept new emails.
Mailbox Full
550
5.2.2
The recipient's mailbox is full and cannot accept new emails.
Mailbox Full
552
5.2.2
The recipient's mailbox is full and cannot accept new emails.
Mailbox Full
552
5.2.2
The recipient's mailbox is full and cannot accept new emails.
Mailbox Full
552
-
The recipient's mailbox is full and cannot accept new emails.


Rate Limit

Category
Code
Enhanced Code
Definition
Rate Limit
221
-
The recipient's server has denied your email. You’re sending mail to is getting too many emails too fast. Please contact the recipient using an alternative method.
Rate Limit
550
4.2.1
The recipient's server has denied your email. You’re sending mail to is getting too many emails too fast. Please contact the recipient using an alternative method.
Rate Limit
550
5.2.1
The recipient's server has denied your email. You’re sending mail to is getting too many emails too fast. Please contact the recipient using an alternative method.
Rate Limit
550
5.2.122
The recipient's server has denied your email. You’re sending mail to is getting too many emails too fast. Please contact the recipient using an alternative method.
Rate Limit
554
5.2.121
The recipient's server has denied your email. You’re sending mail to is getting too many emails too fast. Please contact the recipient using an alternative method.
Rate Limit
554
5.2.122
The recipient's server has denied your email. You’re sending mail to is getting too many emails too fast. Please contact the recipient using an alternative method.

Recipient Error

Category
Code
Enhanced Code
Definition
Recipient Error
450
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
502
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
503
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
510
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
521
5.3.0
Cloudflare’s email routing service indicates that the message encountered an issue related to Cloudflare’s email routing or processing.
Recipient Error
530
5.3.0
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
530
5.7.0
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
530
5.7.1
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
530
5.7.1
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
530
5.7.57
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
530
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
535
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
541
5.4.1
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
4.4.0
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
4.4.2
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
4.4.7
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.1.3
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.1.9
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.3.5
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.103
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.108
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.142
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.300
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.315
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.316
The mail server was unable to deliver the message after repeated attempts. The message eventually "expired" after exceeding the time limit set for retries. This usually happens when the recipient’s server refuses the connection or is unreachable for an extended period.
Recipient Error
550
5.4.317
The mail server was unable to deliver the message after repeated attempts. The message eventually "expired" after exceeding the time limit set for retries. This usually happens when the recipient’s server refuses the connection or is unreachable for an extended period.
Recipient Error
550
5.4.4
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.4.7
The email server has been trying to deliver the message for an extended period but has not been able to do so within the allowable time limit. The email has now been permanently rejected.
Recipient Error
550
5.5.5
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.105
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.124
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.128
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.129
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.133
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.134
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.136
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.193
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.230
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.367
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.51
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.520
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.54
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.64
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.703
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.705
The recipient's tenant in Microsoft 365 (or Office 365) has exceeded a specific limit or threshold, leading to the rejection of further email deliveries. This threshold could relate to various factors, such as the number of messages sent, the volume of inbound messages, or security thresholds based on suspicious activity.
Recipient Error
550
5.7.900
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.902
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.929
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.987
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.7.999
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
550
5.8.2
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
551
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
552
5.7.1
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
553
5.0.0
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
553
5.1.8
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
4.3.5
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.1.0
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.1.2
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.2.0
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.4.6
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.5.4
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.7.1
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
554
5.7.105
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
555
5.7.1
The email platform you are trying to use is not supported for communication with Pixieset's systems. This error suggests that certain types of emails or configurations (e.g., unsupported email clients or formats) are not permitted by Pixieset's mail system.
Recipient Error
556
5.7.1
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
556
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
571
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
577
5.7.7
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
579
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.
Recipient Error
701
-
The recipient's server has denied your email. Communication outside their domain has been restricted. Please contact the recipient using an alternative method.

Rejection

Category
Code
Enhanced Code
Definition
Rejection
450
4.1.8
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
501
5.1.0
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
501
5.1.7
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
501
5.1.8
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
501
5.2.0
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
501
NA
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
533
5.7.1
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.1.0
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.1.0
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.1.7
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.1.8
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.2.3
The email message is too large for the recipient, exceeding their size limit.
Rejection
550
5.4.0
The email has been bounced back due to the email message exceeding the maximum number of allowed hops (transfers between mail servers). This usually happens when there is a mail loop or when the message has passed through too many servers.
Rejection
550
5.4.12
The email has been bounced back due to the email message exceeding the maximum number of allowed hops (transfers between mail servers). This usually happens when there is a mail loop or when the message has passed through too many servers.
Rejection
550
5.4.14
The email has been bounced back due to the email message exceeding the maximum number of allowed hops (transfers between mail servers). This usually happens when there is a mail loop or when the message has passed through too many servers.
Rejection
550
5.4.6
Your email was blocked by the recipient's email provider because a mail loop was detected.
Rejection
550
5.5.2
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.13
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.21
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.23
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.23
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.23
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.24
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.24
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.26
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.27
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.368
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
550
5.7.57
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
553
5.1.8
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
554
5.1.8
These errors indicate that the sending domain does not have valid DNS records. To resolve these issues, please ensure that the sending domain is verified and that the necessary DNS records are added with your DNS provider. Follow these instructions to resolve this issue.
Rejection
554
NA
Possible reasons: the right of the @ in the MAIL FROM does not appear to be valid or poor reputation of a sending domain.

Sender Reputation
How to Fix: Email Blocked Due to Potential Spam or Malicious Activity

  1. Check IP and Domain Blacklists
    Utilize tools like a Blacklist Checker to determine if your IP or domain has been flagged.
    If listed, follow the delisting process provided by the respective Blacklist Service.

  2. Verify DNS Configuration
    Ensure the following DNS records are properly configured for your domain:
  • SPF (Sender Policy Framework)
  • DKIM (DomainKeys Identified Mail)
  • DMARC (Domain-based Message Authentication, Reporting, and Conformance)
    Use tools like MXToolbox to verify the SPF, DKIM, and DMARC records are valid.
  1. Track and Improve Email Reputation
  • Microsoft SNDS: Check your IP reputation with Microsoft services like Outlook and Hotmail.
  • Google Postmaster Tools: Monitor how Gmail handles your emails and analyze deliverability metrics.
  1. Send Emails in Smaller Batches to Build Trust
    To avoid issues, gradually increase the volume of emails sent from new or inactive IPs/domains. Start with smaller batches to establish a positive reputation.
  2. Maintain a Clean Email List
    Regularly remove inactive or invalid email addresses to minimize bounces.
    Utilize email validation tools to ensure your list is clean before launching campaigns.
    Monitor spam complaints and promptly remove problematic contacts.
  3. Follow Best Practices for Email Content
  • Avoid using spam-like language in subject lines (e.g., "Congratulations!!!" or "Act Now!").
  • Balance text and images within your email to avoid sending image-only messages.
  • Ensure all links in your email are secure and not blacklisted.
  • Always include an unsubscribe link in your marketing emails to comply with anti-spam regulations.

FAQs for Email Bounce Classification

1. What is Email Bounce Classification?
Email Bounce Classification is a feature that identifies and categorizes bounced emails based on their causes, allowing users to analyze email delivery issues and optimize their campaigns to reach more recipients effectively.

2. How can I access the Bounce Classification feature?
Go to Settings > Email Services in the Referins platform, and locate the "Bounce Classification" section. This will provide an overview of your email bounces along with insights for troubleshooting.

3. What are the main categories of email bounces?
Common categories include:

  • Mailbox Full: The recipient’s mailbox is full.
  • DMARC/Authentication Issues: Failed authentication due to incorrect DMARC, SPF, or DKIM settings.
  • Sender Reputation: Low sender reputation, causing emails to be flagged as spam.
  • Internal Errors: Issues on the email provider’s end, leading to delivery failures.

4. How can I filter bounces to investigate specific issues?
Use advanced filters in the Bounce Classification dashboard to narrow down results by:

  • Sending domain
  • Email service provider (ESP/ISP)
  • Email type or sending IP
    This helps isolate specific issues based on the chosen parameters.

5. What insights does the Bounce Summary provide?
The Bounce Summary gives you a quick view of total permanent bounces, bounce rates, ESP/ISP blocks, and delivery rates, enabling you to assess the performance of your email campaigns at a glance.

6. How do I resolve issues shown in the bounce details?
Each bounce type comes with actionable guidance:

  • For DNS Issues: Access links to update SPF/DKIM/DMARC records.
  • For Blacklist Problems: Get resources to remove your IP/domain from blacklists.
  • For ISP Blocks: Follow external troubleshooting links to contact providers like Outlook or Gmail.

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