Forza Horizon 1 reached "end of life" status on October 20th, 2016. Forza Horizon 1 and its associated DLC will no longer be available for purchase.
After October 20th, 2016, players who own Forza Horizon 1 can find owned content in their library to download and play the game and its associated content as normal.
Unfortunately, we no longer actively support Legacy Forza titles. Limited support is still available for matchmaking and leaderboard services.