At around 11pm eastern, on September 6th 2011, I was also disconnected on both X360 and PC. Me too, I live in the Montreal area, using Videotron ISP. Now don't get me wrong. I have changed nothing, and everything else beside FF XI works perfect. I searched the web for answer / solutions but couldn't find any. I found someone trying to trace the problem with tracert (trace route dos command) to lobby server, I used 124.150.154.122 (someone pointed out it was the proper ip adress). I do get a time-out at some point between Montreal and Asia. All the ISP could do is acknowledge that there were indeed time out at this point, but since everything else is working fine, and since they have done nothing on their end, they are not going to investigate further. They are positive that the problem is not on their side.

I was able at some point to play for a bit, but today when I finally make it to login (after 50+ attemps) I never actually log coz it stays in downloading info forever and finally times out. Tonight, I can't even connect on 360, and to make sure it was working, i've downloaded random games, 2GB of it.

The problem might not be from SE directly, but sadly there's nothing we can do. Hope it get solved quickly.