Exact response pattern
550 5.6.2 Conversion required and prohibitedPermanentGenericContent
What it means
Delivery would require content conversion that policy prohibits.
Likely causes
- Unsupported encoding or format.
Recommended response
- Send a compatible message format.
Operational rule: Preserve the complete SMTP response, remote hostname, sending IP, envelope sender and timestamp. Never diagnose from the three-digit code alone.