No More Story Quests?

Hello, I'm in a bit of a pickle! I had finished the Ul'Dahn Envoy Main Scenerio quest at level 15. However afterwards I was no longer given any Storyline quests. It just says "No Duties" and it doesn't give me any indication to forward the storyline. I've talked to my FC mates and they found it odd too. Is this possibly a bug? I can't continue the story if I'm not given any story quests! Also, oddly enough my side quests are fine. It's just no story based quests are not appearing at all!

Thank you for your time!

The Ul'dahn Envoy unlocks the airship, you then need to go to Old Gridania to take the next quest: Call_of_the_Sea.