Same issue as OP, but for me, it occurred today, Aug. 8. (I got a new daily quest as normal on Aug. 7.) Americas server. I tried logging in from both my PC and my Android phone.
I also experienced what may be a related issue of a daily quest disappearing. I posted the details of that issue in the Daily Quest Disappeared thread.
The issue of my daily quest disappearing occurred yesterday, Aug. 7, around 12:10a.m. PT. The vanished quest left me with 2 remaining quests and 1 open quest slot.
Then even though I had 1 open quest slot for today, Aug. 8, I didn’t receive a new daily quest today.
I’m posting in both threads in case the issues are separate.