← All status codes4xx – Client Error

HTTP 496 – SSL Certificate Required

(NGINX) The client did not present the SSL certificate required by the server during mutual TLS authentication.

Common use case

Returned when an mTLS-protected endpoint expects a client certificate and the client simply doesn't send one at all.

History

An NGINX-specific extension, the sibling code to 495 for the "no certificate at all" case.

Did you know?

The distinction between this and 495 (invalid certificate vs. missing certificate) helps operators quickly tell misconfiguration apart from a genuine attack attempt.

Other 4xx codes

400Bad Request401Unauthorized402Payment Required403Forbidden404Not Found405Method Not Allowed406Not Acceptable407Proxy Authentication Required408Request Timeout409Conflict410Gone411Length Required412Precondition Failed413Content Too Large414URI Too Long415Unsupported Media Type416Range Not Satisfiable417Expectation Failed418I'm a teapot422Unprocessable Content425Too Early426Upgrade Required428Precondition Required429Too Many Requests430Shopify Security Rejection431Request Header Fields Too Large444No Response451Unavailable For Legal Reasons460Client Closed Connection463Malformed X-Forwarded-For Header464Incompatible Protocol Versions494Request Header Too Large495SSL Certificate Error497HTTP Request Sent To HTTPS Port499Client Closed Request