httpstatuses/contents/codes/421.md

set	code	title	references
4	421	Misdirected Request	Rails HTTP Status Symbol :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 reused¹or 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 controls².

---

• ¹ Connection Reuse RFC7540 Section 9.1.1
• ² Calculating Heuristic Freshness RFC7234 Section 4.2.2
• Source: RFC7540 Section 9.1.2