Its just a really weird issue. The most frustrating part of this issue is the complete lack of support about it.

If you send a ticket, you'll just get a cut-and-paste reply about how it has to do with server congestion. All you can do is try again until you can finally play until SE finally fixes things. Who knows when that'll be.
Its pretty hard to be patient when there's an incredibly tiny amount of info out about it.

Btw, I also get this issue a lot, while I have a friend who has never had issues logging in. Leads me to think that there must be tons of variables involved... so just keep trying. That or quit playing, I guess. As far as I know, that's all you can do.