ok, first of all, a CONNECTION issue should not be listed in a BUG forum unless of course the reason you cant connect to the server is a mirc related bug. Second of all, we would need to know a couple of things:
1) what mirc version?
2) What does the error message say?
3) Are you running a script? If no, are you SURE you're not running a script? (I ask this cause many people download a "clean mirc" only to find out it's a scripted mirc from a friend or other site.)
4) What network is it on?
5) What server(s) and port(s) have you tried?
6) If you were given a URL in the reason you cant connect, did you try it out?
After supplying this info, we might be able to hepl you out better.