I have been seeing similar symptoms - sometimes after going online, it remains stuck at background screen with no controls and no way out except for Alt-F4.

I haven't tried enough times to be sure, but it seems to happen the first time after booting my computer and/or launching from Galaxy - but not always. Could depend on system load with "background tasks" (disk is usually going cracy for a few minutes after boot). Or some specific hardware/os combination too. Little inconvenient, but I never had to retry more than once to actually connect. So for now, I'm giving it time to settle down, it's not gamebreaking here. What I doubt is that it will be different with steam version. In fact, one of the first search hits leads to this, which mentions the same problem. Not initially, but on page 2 the problem description morphs into blank background screen just like here.

If you created your online account without inserting the product key and leaving it's corresponding field blank during registering (serial code), then this account can never go online and you cannot register the product key, again.

I initially thought game was bugged and was ready to demand a refund, until i decided to search for the key in game's shelf and make a new account, this time by typing it down properly. Worked for me.

Hi, KiNgBrAdLeY7

Sorry about that, this bug happened recently prior to the Halloween patch and has already been fixed.
It's not that same case but the other login issues should also be solved.

Have in mind that logging in on Monday from 12:00 to 13:00 GMT+2 is not possible because the server maintenance runs during that time.

If you have other issues you can use the in-game bug reporting tool by pressing the F1 button.