When i try to update WoW BFA i get this message "Something went wrong with a file. We’re not sure what caused it, so please try again or click the code below for more information. Sorry about that! Error Code: BLZBNTAGT00000840 " .
In the morning i was able to play, now not anymore, i tried everything that it’s said here : “https://us.battle.net/support/en/article/23418”