Same issue for me, game just updated when I got home from work, I had a raid with my guild, I tried to log in then got stuck in “retrieving character list”. It loaded once after 10 minutes and it let me see my characters but then while the world was loading I got disconnected. Now when I try to log in, it happens like OP is describing.
Thank you Blizzard, I pay a 15euro subscription per month and I can only play a few hours a week, and I can’t even play when I have the time. The worst is that the raid with my guild was ruined.
There was a similar post a while ago and the fix was on Blizzard’s side.