problem with postfix

[slimvm]

Hello After the upgrade from version 1.0.3 to 1.0.5, there was a problem. Server stopped receiving mail. The server sends the letter. There was a problem when installing the panel version 1.0.3. How to fix, I do not remember. If you need log files, I can write here.

Quote:Message will be retried for 2 more day(s)

Technical details of temporary failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 451 451 4.3.5 Server configuration problem (state 14).