I am not able to connect to MySQL
The error message,
Error No. 2003: Can't connect to MySQL server on 'localhost' (or some other host)
simply means that connection is not possible for one of the following (or similar) reasons:
There is no MySQL server running at the specified host.
Connection to the MySQL server is not allowed using TCP/IP. Check the 'skip-networking' setting in the MySQL configuration file (my.ini on Windows, my.cnf on Unix/Linux). It shall be commented out like '#skip-networking'. If it is not commented out, then do it and restart the MySQL server for the change to take effect. MONyog needs to connect using TCP/IP.
When trying to connect to a MySQL server at an ISP this error message often indicates that direct connection to MySQL has been blocked. You must then use SSH-tunneling to connect.
Some networking issue prevents connection. It could be a network malconfiguration or a firewall issue. We have experienced sometimes that some firewalls (ZoneAlarm in particular) is blocking TCP/IP connections even if it claims to be disabled. Most often it will help to uninstall and reinstall the firewall.