501 Not Implemented
The server does not support this functionality.
What it means
The method is not recognized by the server at all.
What your client should do
Use a different method or endpoint. Retrying will not help.
Should you retry?
No. Repeating the same request will give the same result.
Try it
The free practice API returns this status on demand, with the headers a well-behaved API would send. Call GET /api/play/status/501 from Endpoint Client and open the Explain tab.
Related codes
Defined in RFC 9110. All status codes and headers