The issue is that the maximum number of connections has been reached for the login queue, so the whole thing explodes. I don't know anything about software engineering, servers, etc... however, this is a massive failure on SE's part; the queue breaks if too many players try to connect, which is the whole point of a queue.

If you restart the game and get back into the queue, there is a decent chance your spot will have saved. However, I waited for 2 hours yesterday (rebooting the game multiple times every time I got an error), reached number 1 in queue, got another error, and then was reset back to 5000. I recommend not wasting your time if you get the error, and just play when there are less people trying to connect.

Once you get into the game, you're golden. So connect early in the day, and stay connected.