When trying to log on (with the 2.4.3 client I downloaded from you), it lets me get to realm select, and then I choose Outland. After that, it says "connected" briefly and then "disconnected from server". I tried to make a new account, but I still get the same error. I can confirm that my installation works, because I have been able to play on other TBC servers.
I run on mac, and I use an App file I found online, but with a windows installation of TBC itself - as said, your client.
I've tried wiping cache, wtf, etc, but I haven't been able to find out why.