421 Misdirected Request (HTTP/2) - Client Error Response Status Code

Official Definition

The 421 (Misdirected Request) status code indicates that 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 (Section 9.1.1) or if an alternative service is selected [[ALT-SVC](https://tools.ietf.org/html/rfc7540#ref-ALT-SVC ""HTTP Alternative Services"")].

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.