Exact response pattern
554 5.7.9 Message not accepted for policy reasonsPermanentYahoo/AOLPolicy
What it means
Yahoo permanently rejected the message or sender under policy controls.
Likely causes
- Reputation or complaints.
- Authentication failure.
- Content or URL reputation.
Recommended response
- Inspect the complete Yahoo diagnostic.
- Verify authentication.
- Use Sender Hub support after remediation when appropriate.
Operational rule: Preserve the complete SMTP response, remote hostname, sending IP, envelope sender and timestamp. Never diagnose from the three-digit code alone.