Re: Dragon Age Inauisition can't start dlc

What system are you on?

Did you make sure you downloaded and installed the DLC? It isn't installed along with the main game, even in the Game of the Year edition. If you're on PC, hover over the game with your mouse and click the i button, this should take you to the page where you can download/install your DLC. 

If you have installed your DLC, it's possible that it hasn't 'authenticated'. In order to authenticate the DLC, you have to play the game while logged on to the Dragon Age servers at least once. If you're on PC, you must be logged in on Origin and in game. 

Also, just so you know, the Descent and Jaws of Hakkon DLC should have shown up on your War Table map as soon as you reached Skyhold, and features from Trespasser should have been available as soon as you started the game (custom difficulty settings/trials and having 2 choices of upgrade for each active ability instead of one). The Black Emporium should also have been available on your war table, I believe you can access that even when you're in Haven. So you can play the DLC (other than Trespasser) before the end of the game, once it's installed and authenticated.