There are a number of things that can cause this issue. See the solutions round-up thread pinned to the top of this forum to start. If you require assistance with one of the solutions linked there, please see the read first thread also pinnd to the top of this forum. You can also try the 1.05 beta patch (thread with instructions and links also pinned to the top of this forum) which fixes all DLC authorization issues but can cause increasing load times proportional to the length of play. Restarting the game resets the load times. The devs have been trying for months to track down what is causing the long load times with little success, and have been worki g with a private beta group with multiple iterations of the patch. For now, it is the easiest solution to the DLC issue if you can tolerate restarting the game every few hours or just waiting for the loads.