I'm suffering a similar problem. I'll be fine for hours and hours, so I know it isn't on my end. And then I'll start getting repeated disconnects from the server. This seems to happen mid-day, right when you might expect a lot of people to be logging in, so I suspect their servers just don't have enough peak capacity.
I'm getting that, too, off and on. Now I'm getting a NEW problem! "Disconnected from Gateway Server. Account Ticket Timed Out". I'm getting this whenever I try to log in. Maybe they are just swamped??