4xx Client error
406 Not Acceptable
The server can’t produce a response in a format the client accepts.
Content negotiation failed: nothing matches the request’s Accept (or Accept-Language, Accept-Encoding) header.
Common causes and fixes
- Send
Accept: application/json(or*/*) to an API instead of a narrow or unusual type.
Example response
HTTP/1.1 406 Not Acceptable
Date: Thu, 22 Oct 2026 08:00:00 GMT Check a URL’s status with curl -I https://example.com, which prints the status line and headers.