501
Not Implemented
Server Error
Description
The server does not support the functionality required to fulfill the request
Common Usage
Server doesn't recognize request method or can't fulfill it
Example Response
How this status code appears in HTTP responses
HTTP Response Header
HTTP/1.1 501 Not ImplementedcURL Example
curl -I https://example.com
# Returns: HTTP/1.1 501 Not ImplementedServer Error Response
This is a server error response indicating the server failed to fulfill a valid request.
Related Server Error Codes
Other codes in the same category
500
Internal Server Error
A generic error message when the server encounters an unexpected condition
502
Bad Gateway
The server was acting as a gateway or proxy and received an invalid response from the upstream server
503
Service Unavailable
The server is currently unavailable (overloaded or down for maintenance)