Make sure you have downloaded the 1.2 Fix, which can be found here
However, the lobby does go down from time to time, so please be patient next time.
yes, it can do down sometimes. also, it breaks for me often, just keep trying until it works, sometimes almost 10 times :-(
unless your behind a firewall/router. then its a matter of opening up ports or something. theres details about it somewhere, just use search.