You have to complete your level 10 class (Archer) quest. You get a new class quest every 5 levels. The game doesn't remind you of this, so it's easy to miss this or forget. Generally, you have to head back to the class guild to get it. However, the NPC can change (it did on BLM) and you have to remember where it is. If you forget, you can check your Quest log, Completed tab, Class quests.