Recently when I tried logging in, it would get past the flash screen and the game update progress but would become unresponsive at the server select list. It would show me the list of servers with a flashing diamond icon and gray letters, like the server was down.

Now here's the interesting part... using Avast anti-virus, I right clicked it's tray icon and went to 'avast! shields control' then 'Disable for 10 minutes', a confirmation box would appear and I would click 'No'. But somehow the server would be available for log-in immediately after the confirmation box disappeared. It's worked for me every time like clockwork. No idea why. Hope this helps some of you.