What is “policy rejection”?

Policy rejection indicates administrative rule violations:

What policies might apply:

Sender restrictions: Only accepting from approved senders. Content policies: Prohibiting certain attachment types. Authentication requirements: Requiring SPF, DKIM, DMARC. Encryption requirements: Requiring TLS. Rate limits: Restricting volume from sender.

Policy vs spam filtering:

Policies are explicit rules set by administrators. Spam filtering is probabilistic content analysis. Policies apply regardless of content quality.

Typical codes:

550 or 554 with "policy" in message. 5.7.1 (not authorized by policy). Various custom codes.

Response:

Identify the specific policy violated. Address the underlying requirement. May need to contact recipient administrator.

Policy rejection is the harbor's regulations. Meet the requirements or find another way.