For Jax Quest III on the official server, Ahab wasn't letting me in through the door so I broke in to his office through the deck.
He's not talking to me about the quest. I didn't have this problem in single player. Is there some block protection enabled? I had no problem advancing HQM quests or NPC quests today until this point so it's not a questing problem in general. After disconnecting and reconnecting, Ahab got my quest moving again. Still no idea about the door not letting me through, though.
Speaking of the official server, if you're going to steal from the town, I wish you'd at least patch up the building afterwards! There's a hole in the mage's tower where the blood altar used to be. Looks hideous.