AC: Revelations multiplayer problem

Hello folks. I tried some forums and googling but had no success to solve this problem. I used to play a lot (and still play) AC: Brotherhood multiplayer, with no problem, even after the Uplay update.

But since this update I cannot join ANY multiplayer game in AC: Revelations. I think it is very strange that I can play AC: B mp but not AC:R.

Anyone had this problem and solved could help me?

Thanks.