501 Error Code Explained
The server either does not recognise the request method, or it lacks the ability to fulfill the request.
Why it occurs
The error occurs when the Web server does not understand or does not support the HTTP method it finds in the HTTP data stream sent to it by the client. The method in the request HTTP data stream should be one of the following GET, OPTIONS, HEAD, POST, PUT, DELETE, TRACE and CONNECT as defined by the HTTP protocol Or the method may be valid but not actually supported by the Web server.
Fixing 501 error code
The client should specify a valid request type. Even after that if the Web server is responding incorrectly, then the web server simply needs to be upgraded to fix the issue.
If you are registered with 100pulse, your site will be monitored and you will be intimated by an email or a short message service when 501 status code error occurs.