Recently I had noticed some quests not receiving progress when playing games. Currently I have some class specific daily quests (play 3 games as…), and one of them specifically mentions Death Knight. I have played a few games as a Death Knight today but have not received any progression in the quest (still says 0 out of 3 games). A different quest (play 30 cards, I refreshed for this one), completed just fine. It is only these class specific quests that do not appear to be gaining progression.
What game mode were you playing?
Some quests count progress from all game modes except solo adventures, whereas others only count progress from ranked games.