Basic SMTP reply code · RFC 5321
354 Start mail input
After DATA: the server waits for the message, ended by a line holding only a dot.
- Class: 3yz · Intermediate reply
3yz: the command was accepted and the server waits for the rest (for example the content after DATA) (RFC 5321 §4.2.1). - Associated enhanced codes
The IANA registry pairs no enhanced code with this one.
- Source
Have the whole error message?
Sources: RFC 5321 · RFC 3463 · RFC 3464 · IANA · Gmail · Microsoft 365 · read on 26 September 2026