BLZBNTBNA00000005 (Battle.net Agent Went to Sleep)
The solution
go to /home/user/Games/battlenet/drive_c/ProgramData/Battle.net/Agent/
leave directory Agent.9098
delete directory Agent.9124
for me I was able to launch the game. I had some other problems with freezing game too, so I used the “continue offline” option and exit the battle.net window once game is launched and log in through the game.