Getting same here, "You are not allowed to log in to this server at this time". Don't even get to the "Choose your character" screen. I know I got a bugged mission that I was trying to complete, and it would not complete and I couldn't reset it. Tried logging out and back in, and this is the message I get. Hopefully they will get the login servers back up soon.
Server isn't down you can get in but have to log in over and over again till you get lucky and connect. Also I am having the problem of getting disconnected every minute or two. What happened here the stability really improved last week then over the weekend and today it seems the server is extremely unstable just like day one.