What Is a 421 Status Code?

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 reused¹ 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 controls².

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

421 CODE REFERENCES

Rails HTTP Status Symbol :misdirected_request

.NET HttpStatusCode.MisdirectedRequest

Rust http::StatusCode::MISDIRECTED_REQUEST

Go http.StatusMisdirectedRequest

Symfony Response::HTTP_MISDIRECTED_REQUEST

Python3.5+ http.HTTPStatus.MISDIRECTED_REQUEST

Apache HttpComponents Core org.apache.hc.core5.http.HttpStatus.SC_MISDIRECTED_REQUEST

Angular @angular/common/http/HttpStatusCode.MisdirectedRequest

How to troubleshoot a 421 status code

If you encounter a 421 status code, it is recommended to check the documentation or seek support from the application or server vendor for more information about the specific cause of the status code. In addition, you can try the following general troubleshooting steps:

• Check the server logs: Look for any errors or warnings in the server logs that may provide more information about the cause of the status code.
• Verify network connectivity: Ensure that there are no network connectivity issues between the client and server that may be causing the status code.
• Verify credentials: If the 421 status code is related to authentication, verify that the client is using the correct credentials to access the resource.
• Check server configuration: Review the server configuration to ensure that it is set up correctly and that all necessary dependencies are installed and configured.
• Check for updates: Make sure that the application or server is running the latest version and that any necessary updates or patches have been applied.

Additional resources

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