Exact response pattern
252 Cannot VRFY user, but will accept messageInfoGenericRouting
What it means
The server cannot verify the mailbox during SMTP but is willing to accept the message.
Likely causes
- VRFY is disabled or restricted.
Recommended response
- Continue delivery and rely on the final delivery status.
Operational rule: Preserve the complete SMTP response, remote hostname, sending IP, envelope sender and timestamp. Never diagnose from the three-digit code alone.