Front desk · HTTP Status Codes
4×× Client Error
417 Expectation Failed
· filed 2026-07-18 · click a code to copy
HTTP 417 Expectation Failed is a client error-class status code defined in RFC9110. The expectation in the Expect header could not be met.
Client-error responses signal that the problem is on the requesting side: the request is malformed, unauthorized, or aimed at something that isn't there. On the wire, the response begins with the status line HTTP/1.1 417 Expectation Failed.