it's not the server, i play on Lich as well. Did you try it just now? If so it might be because not many people are online at the moment, it's noon in europe now and Lich is an european server, so not many people will be online.

Which dungeon do you need? I can help you this evening (it's 11:45 now here) if you want. I got a lvl 24 tank, finding a group should be a matter of seconds.