At this time it appears that the door is bugged for the quest Maniac Manor. The quest currently says to "seek entry into Haukke Manor" and the door itself has a glowing sparkle on it. However when you try to click it to activate it nothing happens.

This issue is newish, since I was able to complete this quest back a few weeks ago when I did it, and now it isn't working for another character/account.

This is different from the other bug reported about unable to receive the quest from the NPC. The quest was able to be gotten, and now we are unable to "open the door"