451 Requested action aborted Reject due to policy restrictions

Reason

Emails from your domain were not signed by DKIM, although this is to be expected. Due to this missing DKIM signing and an unexpectedly high email traffic, the acceptance of your emails was temporarily rejected.

Solution

To avoid further throttling, please sign your emails again using DKIM.

Please make sure to support DKIM alignment, the DKIM domain must match your From domain (RFC 5322.From), at least in relaxed form.

Below you will find examples that illustrate this requirement:

Example 1 (relaxed DKIM alignment)

DKIM Domain: example.com
From Domain(RFC 5322.From): child.example.com

Example 2 (relaxed DKIM alignment)

DKIM Domain: child.example.com
From Domain(RFC 5322.From): example.com

Example 3 (strict DKIM alignment)

DKIM Domain: example.com
From Domain(RFC 5322.From): example.com

Example 4 (strict DKIM alignment)

DKIM Domain: child.example.com
From Domain(RFC 5322.From): child.example.com

If this does not help you, you or the person responsible for managing your system can contact us using the following form.

Please let us know the DKIM domain you use to sign your emails.

Name

Email address

Company (optional)

Message (optional)

Security check