Sudden glitch in joining TC/ICP games

[JCSahyan]

Hello again, folks. I'm afraid I'm back with yet another query, presuming again on everybody's good nature.
My girlfriend and I have been playing Diablo 2 in TC/ICP mode for some time, and loving it. Suddenly, it won't let her join a game I'm hosting. (We sort of take turns hosting.) I have no problem joining "her" game, but, when I host, she gets a message saying "Cannot connect to server." (I assume we're on the same server, based on the fact that our computers are something on the order of six feet apart, and we use the same realm, obviously. I suppose I might be making an unwarrented assumption, but...if it's a matter of different servers, why would it have started only a day or two ago?
Anyway, as seems obvious, I'm very, very far from a techie, and I've no notion what's going on, except that it's screwing things up for us. Does anybody have any idea at all what might, even possibly, be the problem? I'd appreciate more than I can say, any help anybody can give. (You see, my Barbarian and her Amazon are just about to go make things annoying for Baal, and, well, for things to go nuts this close to the end is just, well......Anyway, thanks.)

[rumph]

Well, I'm no techie either, plus, a bit of a newbie, but the last time I had someone over and we tried to play the network game, one of us had trouble hosting and found out that it was because I had the "windows firewall" enabled. That's presuming you have a Windows machine, of course, but you can turn that off in the property tab for your network connection.

It makes me feel a bit antsy to do this, of course, so I usually turn it back on when I'm done!

[HardyTarget]

Have you checked the IP that it hasn't changed?
If you haven't touched your firewall/router -options at all, then it's most likely just a different IP.