The error code is BLZBNTBGS80000011.
I also struggled to log into the forums. All related apps are allowed through my firewall on my laptop. My internet connection is fine as I can browse freely on both mobile and laptop. This started around 12:45am EST on 6/23.
- While writing this it seems I can log back in to the Battle.net app as of 1:50am, but I think there might be connectivity issues remaining. Still can’t log into World of Warcraft itself, getting error code BLZ51901016.