Had trouble logging into Battle.net lately? Blizzard knows, and unfortunately, they are still investigating why.
Blizzard confirmed that they are in the middle of investigations after a spate of complaints hit reddit. Of course, given recent hacks, there is heavy suspicion that the Battle servers were hacked, only Lizard Squad and other hacker groups have not taken responsibility.
So, it is entirely possible this is a bug on Blizzard’s end. If you play World of Warcraft or Hearthstone, you should wait it out for word from Blizzard.