I have played Forza Horizon a bunch, then I upgraded my Motherboard/Processor today. Now, when I start this app I get the above error. It is not in my library anymore after following these instructions: https://answers.microsoft.com/en-us/windows/forum/windows_10-windows_store/windows-store-error-code-0x803f8001/8efabd43-d9e9-4d3e-9aa0-7e6b32da0a80
Thankfully I paid via paypal and will get my money back if I'm not able to play this game, as I was enjoying it and upgraded to be able to play it on ultra.