Exact response pattern
530 5.7.0 Authentication requiredPermanentGenericAuthentication
What it means
The server requires SMTP authentication before the requested action.
Likely causes
- Client attempted relay without AUTH.
- Submission port policy.
Recommended response
- Enable SMTP AUTH.
- Use the correct submission port and TLS policy.
- Verify the account is permitted to send.
Operational rule: Preserve the complete SMTP response, remote hostname, sending IP, envelope sender and timestamp. Never diagnose from the three-digit code alone.