I actually tried to play a new Settlers Beta I received from Ubisoft yesterday and experienced this. After half an hour I caved in and gave up. Gamers are unable to play Assassin's Creed 2 as the DRM servers required to authenticate the game went down. This game has a new pesky DRM scheme that requires you to be online at all times, this means you can't continue to play when your Internet connection is down, but it also means you're totally screwed when Ubisoft's DRM servers go down. And funnily enough, people who pirated the game have no problem playing it.. This is another great example of an anti-piracy scheme that totally backfires and only hurts the people who actually bought the game.
Well, as it turns out, when the Ubioft severs go down, no one can play their games and Ubisoft customers get very upset. At around 8am GMT, people began to complain in the Assassin's Creed 2 forum that they couldn't access the Ubisoft servers and were unable to play their games. Fast forward ten hours and it seems that the problem still hasn't been resolved, despite the assurances from a Ubisoft representative that the servers were 'constantly monitored'
"I don't have any clear information on what the issue is ... but clearly the extended downtime and lengthy login issues are unacceptable, particularly as I've been told these servers are constantly monitored," said 'Ubi.Vigil', adding, "I'll do what I can to get more information on what the issue is here first thing tomorrow and push for a resolution and assurance this won't happen in the future."