HTTP Status Code 421 – Misdirected Request

The request was directed at a server that is not able to produce a response. This can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI.

Clients receiving a 421 Misdirected Request response from a server MAY retry the request — whether the request method is idempotent or not — over a different connection. This is possible if a connection is reused or if an alternative service is selected ALT-SVC.

This status code MUST NOT be generated by proxies.

A 421 response is cacheable by default, i.e., unless otherwise indicated by the method definition or explicit cache controls.