The most obvious fix for a bugged quest is to completely log out of the game for about fifteen minutes. Which typically causes the quest in question to reset. The less obvious fix is to abandon any group dungeon quests you may have in your journal. Especially if you attempted, but didn't complete them. They seem to cause a great many of the problems to do with broken quests.
I really wish this fact was more publicized by this community. I repeatedly have to tell people in game to do this if a quest is broken for them, and it seems to almost always work. Basically it isn't usually the quest that is broken, but that the group dungeon quest is conflicting with the current quest the player is on.
Anyway it is a quick fix attempt that doesn't cost anything, and often the effect is instantaneous. Last night I had a quest hang on me, and abandoned a group dungeon quest, and voila the quest I was attempting immediately began to run flawlessly. It isn't like you can't go back and reacquire them later.