421
Misdirected Request
Client errors (4xx)·RFC 9110
What 421 means
The request was sent to a server unable to produce a response for it.
Seen with HTTP/2 connection coalescing when a reused connection does not serve the target authority.
Client errors (4xx)
The request contains an error from the client — bad syntax, missing auth or a wrong URL.
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 Content423Locked424Failed Dependency425Too Early426Upgrade Required428Precondition Required429Too Many Requests431Request Header Fields Too Large451Unavailable For Legal Reasons
FAQ — 421
What does HTTP 421 mean?
421 Misdirected Request: The request was sent to a server unable to produce a response for it. Seen with HTTP/2 connection coalescing when a reused connection does not serve the target authority.
Which class does status code 421 belong to?
421 is a Client errors (4xx) code. The request contains an error from the client — bad syntax, missing auth or a wrong URL.
Where is the 421 code defined?
Status code 421 is defined in RFC 9110 and is part of the IANA HTTP Status Code Registry.