"Method not allowed": generally returned if a client attempts to use an incorrect method (such as POST) for a request to a particular URL.
Web servers return the HTTP status code 405 in response to requests using a particular method for a given URL that are not among the methods the server allows for that URL. 
For example, the https://developer.mozilla.org server allows the GET method for the URL https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/405 but disallows the POST method. A POST to that URL causes the server to send a response with HTTP status code 405.
That response also includes the response header Allow: GET, PUT, HEAD.
According to the HTTP specification http://httpwg.org/specs/rfc7231.html#status.405:
The origin server MUST generate an Allow header field in a 405 response containing a list of the target resource's currently supported methods.
 
     
     
     
     
     
     
     
     
     
     
     
     
     
    