What does a permanent error mean in an email? - Quora
What is DMARC Evaluation? - How to evaluate DMARC Policy
Troubleshooting "Email Rejected per DMARC Policy" [SOLVED]
DMARC reporting - MailerCheck
What does this undelivered email returned to sender error mean? '451 4.7.5 Temporary error evaluating DMARC policy (in reply to end of DATA command)'? - Quora