I get an error message “Warning: Unknown Error (0)” and authentication fails.

An error message “Warning: Unknown Error (0)” and authentication fails

If you find an error message “Warning: Unknown Error (0)” and authentication was fail,
most likely it is realted with authentication server.
The connection to authentication server seems to be blocked for some reasons. 

Firstly, please confirm whether your computer is connected to internet.

Secondly, security software or firewall may block the connection. Please kindly ask your system administrator and allow connection to the authentication server.
If you can’t identify the server to allow please contact us.