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HTTP error
501 Not Implemented
The server does not support what the request asks for.
What it means
The server does not recognise the request method or cannot carry it out. It usually means the feature does not exist on this server, not that something broke. Retrying will not help until the server is changed.
Common causes
- An HTTP method the server does not support
- An outdated web server or proxy
- An API endpoint that was declared but not built
- A misconfigured proxy between the client and the application
How to fix it
If you are a visitor
- Update your browser or app
- Try again later, or contact the site if the problem stays
If you run the site
- Check which methods your server and application accept
- Update the web server or proxy
- Return 405 Method Not Allowed if the method is known but not allowed on this address
Catch it before your users do
You can check the status code of any address right now. To hear about 501 errors as they happen, an HTTP(S) monitor requests the page around the clock, compares the response with the status codes you expect and alerts you when it does not match.
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