Unprocessable Content
The request was well-formed but could not be followed due to semantic errors in the contained instructions.
422
422
Session Interval Too Small
The Session-Expires value in the request is smaller than the minimum timer value supported by the server. The response includes a Min-SE header indicating the minimum acceptable interval.
References
Mailbox full
The recipient mailbox has exceeded its storage quota. The message may be retried later if the mailbox is cleared.
References
Unprocessable Content
Originally introduced by WebDAV (RFC 2518, section 10.3) to indicate that the request was syntactically well-formed XML but semantically invalid — for example, a PROPPATCH body containing unrecognised property values. Now adopted into the base HTTP specification (RFC 9110).