I got locked out at lvl 47, and could not get back in via the NPC. I tried flying to gridania and back, as well as limsa. Nothing worked.

What did work, was to travel manually to the waking sands, which is the stronghold from the story, located in western thanalan / vesper bay. Right outside the big door was Cid, and the quest turn in.

I found this thread while googling a solution, perhaps someone else will see this and it will help