HTTP 417 — Expectation Failed
The server cannot meet the requirements of the Expect request-header field
When to use it
Use status 417 when this is the correct HTTP response semantic: The server cannot meet the requirements of the Expect request-header field
Request and response example
GET /protected-resource HTTP/1.1
Host: api.example.com
HTTP/1.1 417 Expectation Failed
Content-Type: application/json
{"error":"Request cannot be completed"}