I've been able to get on the TBC server without a hitch this past week. Today I got home and I got stuck at the "Connecting" prompt. Eventually leading to "Unable to connect." It didn't make much sense as I knew I had a connection. So I tried a few things.
I tried going into my firewall and allowing the program, dumping my DNS through msconfig, re downloading the client, as well as resetting the Realmlist folder.
Even after doing that I still had the same conclusion. Stuck at the "Connecting" prompt.
If anyone has a fix or knows what's going on some help would be greatly appreciated! Especially since I love the server :X
I have the same issue and also tried everything you mentioned. One thing you didn't mention is resetting your router, I heard that worked for someone before. This type of thing has happened to me twice before on private wow servers and I had no choice but to abandon the game. If you do find a solution please share it.
I called my ISP before about it and they said there's nothing on their end that would deny access, but nobody mentioned changing IP's. I hope that works for you.
I have some new information that may shed some light on the source of the problem, if indeed they are related. This problem originally hit me about 2 months into playing on Elysium so I decided to go back and browse there support pages for any new information.