5.7.0 — Other or undefined permanent security status

What this code means

The message was permanently rejected because of a security-related problem, but the response does not describe it more precisely. Do not retry the unchanged send.

Technical meaning

The X.7.0 pattern means that the message was returned because of a security-related condition that cannot be properly expressed by another available detail code. The code may also be used when an applicable security policy prevents the condition from being described more precisely. In the concrete 5.7.0 code, the leading digit assigns the result to permanent class 5.

Delivery status

The leading digit 5 denotes a permanent failure of the current attempt. The code alone identifies neither a particular security mechanism, policy rule, nor responsible party, and it does not establish that the recipient address is invalid.

Class: Permanent failure
Retry: Do not retry unchanged
Suppression: Check the full context

Retry decision

Operational guidance: stop automatic and manual retries of the same unchanged send. Consider a new send only after establishing the cause from the full context and confirming a relevant change in the condition or configuration.

Suppression decision

Operational guidance: do not automatically suppress the address based on general code 5.7.0 alone. Inspect the full response, security context, delivery history, and other permanent signals; make the suppression decision only according to the established cause and applicable policy.

Common causes

A permanent security-related condition caused the message to be returned, but the reporting system could not describe it with a more specific available code.
An applicable security policy may have prevented the system from disclosing a more precise description of the condition.

Diagnostic steps

Inspect the raw SMTP response or delivery report and confirm that the enhanced code is exactly 5.7.0 and that the basic reply is in the 5xx class.
Correlate the response with the intended message, attempt time, transaction stage, and system that returned the code; retain the full response text and available security context because the code itself is general.
Inspect available logs to determine whether the system recorded a more specific X.7.x condition or limited detail under its security policy; do not assign a specific cause from 5.7.0 alone.
Stop unchanged retries; before any new send, confirm a relevant change and check suppression state again.

Actions by owner

Sender

Confirm that the send was intended and that the recipient should still receive the message; give the sender administrator the attempt time and complete available context without manually retrying the unchanged send.
Do not change credentials or security settings based on the code alone; follow only a confirmed administrator instruction.

Sender administrator

Stop retries of the unchanged send and retain the raw response, time, transaction stage, and system that returned the code; check suppression state and available logs without assuming a specific cause.
Give the collected context to the recipient administrator or provider if the cause remains unclear; permit a new send only after a relevant change has been confirmed and suppression has been checked again.

Recipient administrator

If the code came from a recipient system you manage, inspect its security and policy logs for the specified time and attempt to identify a more precise condition when policy permits disclosure.
Correct the confirmed condition within your control if delivery should be allowed; otherwise provide the permitted context and, when safe, return a more specific status code.

Provider

If you operate a system involved in the attempt, inspect managed-service logs and the security rules applied at the specified time; do not assign a particular cause from the code alone.
Correct the confirmed problem in the managed layer or preserve the intended policy rule; when policy permits, return a more specific X.7.x code instead of general 5.7.0.

Verified provider examples

Verified provider examples for 5.7.0 appear below, from Rackspace Email. They show real provider practice for this response and do not redefine the standard 5.7.0 meaning or cover every occurrence.

Rackspace Email hosted mail · SMTP 550

Exact SMTP response

550 5.7.0 [blocked file] - File attachment is not allowed because they can be used to exploit Winzip (G1C)