Server error
501 501 Not Implemented
The server does not support the functionality needed to fulfil the request — typically an HTTP method it does not recognise.
Common causes
- A proxy that does not understand a method or protocol upgrade.
How to fix it
- Rare on real sites. Check whether a proxy or CDN is intercepting the request.
See what a site actually returns
Run a live check and read the real status code, headers and timings.
Other status codes
200 OK
201 Created
204 No Content
206 Partial Content
301 Moved Permanently
302 Found
303 See Other
304 Not Modified
307 Temporary Redirect
308 Permanent Redirect
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
405 Method Not Allowed
408 Request Timeout
410 Gone
413 Payload Too Large
418 I'm a Teapot
429 Too Many Requests
451 Unavailable For Legal Reasons
500 Internal Server Error
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
507 Insufficient Storage
508 Loop Detected
521 Web Server Is Down
522 Connection Timed Out
523 Origin Is Unreachable
525 SSL Handshake Failed