HTTP 496 SSL Certificate Required
Updated Free mock REST & WebSocket APIs
HTTP 496 SSL Certificate Required — nginx: a client certificate was required but none was provided.
- Class
- 4xx Client Error
- Defined in
- Unofficial (nginx)
- Official
- No — nginx-specific
- Cacheable by default
- No (unless Cache-Control/Expires say so)
- Safe to retry
- Not without changing the request
Try it: get a real 496 response
Our test endpoint answers every request with 496 SSL Certificate Required.
curl -i https://mockfox.dev/api/status/496Use it in tests, health-check monitors or to see how your client handles a 496. Add ?delay=2000 to slow it down.
What does HTTP 496 mean?
With ssl_verify_client on, nginx returns 496 (shown to the client as 400 "No required SSL certificate was sent") when the client didn't send a certificate. Configure the client (curl --cert/--key, a browser certificate store) or use ssl_verify_client optional for routes that don't need mTLS.
How to fix 496
- Visitors: Reload the page, check the address for typos, and clear the site's cookies. If it persists, the site owner needs to fix it.
- Developers: Read the response body and server logs for details, fix the request (method, headers, body, credentials) and return a clear error message to clients.
Example 496 response
HTTP/1.1 400 Bad Request Server: nginx Content-Type: text/html # (logged internally as 496)
4xx Client Error: The request contains an error or can't be fulfilled — fix the request before retrying. See the full list of HTTP status codes.
Related status codes
- 495 SSL Certificate Errornginx: the client presented an invalid TLS client certificate.
- 400 Bad RequestThe server can't process the request because it's malformed or invalid.
- 401 UnauthorizedThe request lacks valid authentication credentials; it must include a WWW-Authenticate challenge.
Related tools
Frequently asked questions
What does HTTP 496 SSL Certificate Required mean?
nginx: a client certificate was required but none was provided.
Is 496 a client or a server error?
496 is a 4xx code, so it signals a problem with the request (as seen by the server). Retrying the identical request usually gives the same result.
Is 496 an official HTTP status code?
No. It isn't in the IANA HTTP Status Code Registry; it's specific to nginx. Generic HTTP clients treat it as an unknown 4xx status.
How can I test how my app handles a 496?
Call https://mockfox.dev/api/status/496 — it responds with 496 to any method, with CORS enabled. Add ?delay=2000 to simulate a slow response.