Dailies reset in 5 minutes... try again?
If you complete 2 dailies at the same time while having 4/5 dailies complete, it bugs and you don’t get a chest.
Supposedly, if leveling up is one of the dailies and you complete a daily while having 4/5 dailies completed and level up because of it, getting a 6th daily, it bugs and you get 2 chests.