Yeah the given solutions are poor. I've never had an issue so prevalent for an online game. Most other PC games I've had just work. I've probably wasted a good 2-3 hours trying to get this to work to play with my younger brother. I shouldn't have to reset IP settings to play a game... why is this the only game I have where this needs to be done?
Also, why is there no error code? You'd think it'd be relatively easy to slip in some sort of error code to help the user debug an issue. Not simply "unable to connect".
Disappointing.