Is Vade's use of 550 5.7.1 a hard bounce, and what do the error codes mean?

Summary

A `550 5.7.1` error generally signifies a permanent delivery failure and is often treated as a hard bounce, typically related to security policies, delivery restrictions, or sender reputation issues. However, Vade's specific implementation is a concern because they use this code broadly, requiring users to check their webpage for clarification. Experts emphasize checking the full error message or SMTP response from the receiving server, as the specific reason for the rejection depends on the server's configuration. Some services treat `5.7.1` strictly as a hard bounce with automatic address suppression, and the SMTP code is highly variable and you should check all the responses to see why it failed.

Key findings

  • Hard Bounce Indicator: `550 5.7.1` usually indicates a hard bounce and permanent delivery failure.
  • Security/Policy Related: The error is often due to security policies, recipient server restrictions, or sender reputation problems.
  • Vade's Non-Standard Use: Vade's broad use of `550 5.7.1` is non-standard, necessitating checking their webpage for details.
  • Implementation Matters: The exact meaning of `5.7.1` can vary depending on the mail server and service.
  • SMTP Responses provide clarity: You should check the full message or SMTP Response for clarity and reasons why it failed

Key considerations

  • Check Full Message: Always examine the complete error message/SMTP Response from the receiving server to understand the specific rejection reason.
  • Investigate Restrictions: For Exchange Server, investigate sending limits and permissions if encountering `5.7.1` NDRs.
  • Bounce Handling Procedures: Follow recommended bounce handling procedures for the specific service (e.g., suppression in Amazon SES).
  • Double check: Double check all the responses as the code itself is highly variable.

What email marketers say
9Marketer opinions

The consensus is that a `550 5.7.1` error generally indicates a hard bounce due to permanent delivery failure, often related to security policies or sender reputation issues. However, several sources emphasize the importance of examining the full error message from the receiving server for a precise understanding of the rejection reason, as the code itself can be used for various specific issues. Some also state it's crucial to look at the text portion of the SMTP response for clarity.

Key opinions

  • Hard Bounce Indicator: `550 5.7.1` typically signals a hard bounce, implying a permanent delivery failure.
  • Security/Policy Related: The error often stems from security policies, recipient server restrictions, or sender reputation problems.
  • SMTP Response Clarity: It's important to look at the text portion of the SMTP response for clarity.
  • 5xx codes indicate an error: 5xx codes are always a delivery error and treated as a hard bounce

Key considerations

  • Detailed Error Message: Always check the complete error message from the receiving server for the specific reason behind the bounce.
  • Policy Verification: Investigate the specific policies or security measures causing the rejection before automatically categorizing it as a hard bounce.
  • Diagnostic Code: Look at the full diagnostic code to check the original failure reason in the bounce messages.
Marketer view

Email marketer from MailerQ explains that although `5.7.1` often indicates an issue with anti-spam policies it's still worth checking what policies are in place before automatically classing as a hard bounce

July 2022 - MailerQ
Marketer view

Email marketer from Mailjet shares that a `5.7.1` error usually indicates a permanent failure and should be treated as a hard bounce. They suggest reviewing your sending practices to prevent such errors.

August 2024 - Mailjet
Marketer view

Email marketer from Litmus Community Forum explains that it's crucial to look at the text portion of the SMTP response for clarity and that the `5.7.1` response is a permanent failure and should be treated as a hard bounce.

July 2022 - Litmus Community Forum
Marketer view

Email marketer from Mailgun says that although `5xx` codes are errors and treated as hard bounces, they state that you should check all bounce messages and look at why the original message failed - the full diagnostic code as there could be different issues such as anti-spam policies.

January 2022 - Mailgun
Marketer view

Marketer from Email Geeks shares that they have the Vade's `550 5.7.1` code set as a hard bounce based on their documentation.

November 2022 - Email Geeks
Marketer view

Email marketer from Reddit suggests that while `5.7.1` usually indicates a hard bounce due to security or policy reasons, it is crucial to check the full error message from the receiving server to understand the specific reason for the bounce, because sometimes it is for other reasons.

March 2023 - Reddit
Marketer view

Email marketer from Stack Overflow indicates that `550 5.7.1` often means "Delivery not authorized, message refused". It's usually a permanent error so should be treated as a hard bounce.

October 2022 - Stack Overflow
Marketer view

Email marketer from GlockApps suggests that `5.7.1` is generally treated as a hard bounce. However, they emphasize that you should check the detailed response from the receiving mail server to fully understand the reason for the rejection.

February 2022 - GlockApps
Marketer view

Email marketer from Email on Acid explains that `5xx` errors are generally permanent failures. A `5.7.1` code can signal recipient server security policies or sender reputation problems which result in being a hard bounce.

March 2024 - Email on Acid

What the experts say
6Expert opinions

Experts agree that while a `550 5.7.1` error indicates a permanent delivery failure, Vade's specific implementation raises concerns. Vade uses this code broadly, making it difficult to discern the exact cause without consulting their webpage. This deviates from SMTP standards, where different codes should signify distinct failures (e.g., `550 5.1.1` for "user unknown"). The actual reason for the rejection depends on the receiving server's configuration and should be reviewed in the returned message.

Key opinions

  • Vade's Internal Code: `_403` is Vade's internal code for `550 5.7.1`, but their documentation URL is incorrect.
  • Non-Standard Use: Vade's use of `550 5.7.1` for multiple rejection types is non-standard and problematic.
  • Delivery Policy/Security: The `550 5.7.1` error usually indicates a delivery policy violation or security restriction.
  • Error Code Variability: The specific cause of a `550 5.7.1` error is highly variable and depends on the receiving server.

Key considerations

  • Check Full Message: Review the specific message returned with the error code to understand the exact reason for the failure.
  • Potential Misinterpretation: Be aware that Vade's broad use of `550 5.7.1` may lead to misinterpretations without additional investigation.
  • ESP is wrong: The ESP is wrong if it blames Vade for the SMTP error code itself, as the 403 isn't an SMTP error code. The first 3 digits in an error message is the error code.
Expert view

Expert from Email Geeks explains that `_403` is Vade's internal code for `550 5.7.1` and points out that their site's URL is incorrect.

November 2022 - Email Geeks
Expert view

Expert from Word to the Wise notes that the `550 5.7.1` status code is highly variable. While the first number indicates it's a permanent error, the specific cause depends on the receiving server's configuration. The best course of action is to review the specific message returned along with the error code.

May 2024 - Word to the Wise
Expert view

Expert from Email Geeks shares that Vade is making things extremely difficult by using `550 5.7.1` for every rejection, forcing people to check a webpage for explanations of their esoteric codes.

January 2022 - Email Geeks
Expert view

Expert from Email Geeks highlights issues with Vade using `550 5.7.1` for "user unknown", explaining that it is not clearly defined in the spec and they should be using `550 5.1.1` instead.

October 2024 - Email Geeks
Expert view

Expert from Email Geeks states that the ESP is wrong, as the 403 isn't an SMTP error code. The first 3 digits in an error message is the error code.

January 2023 - Email Geeks
Expert view

Expert from Spam Resource explains that a `550 5.7.1` error typically indicates a delivery policy violation or security restriction. They are unable to provide a more specific reason without additional context from the bounce message.

July 2022 - Spam Resource

What the documentation says
4Technical articles

Documentation sources indicate that a `550 5.7.1` error, as defined by SMTP enhanced status codes, generally signifies a permanent delivery failure due to security or policy rejections. While the standard provides a framework, specific implementations can vary, with some services like Amazon SES treating it definitively as a hard bounce and automatically suppressing affected addresses. Microsoft Exchange Server interprets it as a delivery restriction or policy issue, suggesting investigation into sending limits and permissions.

Key findings

  • Permanent Failure: `5.7.1` signals a permanent delivery failure.
  • Security/Policy Rejection: The error usually stems from security policies or delivery restrictions.
  • Implementation Variation: The specific meaning can vary depending on the mail server implementation.
  • Hard Bounce Treatment: Some services, like Amazon SES, treat it strictly as a hard bounce with automatic suppression.

Key considerations

  • Investigate Restrictions: If using Microsoft Exchange, investigate sending limits and permissions to resolve the issue.
  • Sender Reputation: Be aware that repeated `5.7.1` errors can negatively impact sender reputation.
  • Bounce Handling: Handle `5.7.1` bounces according to the specific service's recommendations (e.g., suppression in Amazon SES).
Technical article

Documentation from Microsoft explains that in Exchange Server, a `5.7.1` NDR (Non-Delivery Report) often indicates a delivery restriction or security policy preventing the email from reaching the recipient. It suggests that the sender should investigate sending limits and permissions.

February 2024 - Microsoft
Technical article

Documentation from IETF explains that SMTP enhanced status codes, including the `5.7.1` code, provide a standardized way to indicate permanent delivery failures related to security or policy rejection. However, the specific meaning can vary by implementation.

March 2021 - IETF
Technical article

Documentation from Amazon Web Services explains that Amazon SES treats `5.7.1` errors as hard bounces, indicating a permanent issue. SES automatically suppresses these addresses to protect sender reputation.

June 2022 - Amazon Web Services
Technical article

Documentation from SparkPost says that a `5.7.1` response code typically indicates a permanent bounce, often due to a policy or security filter on the recipient's side, making it a hard bounce.

January 2022 - SparkPost