Hi @pilotskcx,
Had the same issue (Purchase Failed). Here is what fixed it for me:
Go to: https://account.microsoft.com/
Under Payment & Billing at the top - Select “Manage”
Update old credit card info / incorrect address
Restart sim
Edit: On a subsequent purchase I also received purchase failed. I clicked on my profile / avatar and chose Sign Out. I also exited the sim and launched it from the Xbox application. Was able to purchase after that.
If the problem continues, suggest searching for “Purchase Failed” in quotation marks here in the forum. Keep us posted if you get it resolved.
Also, if you are using Steam, here is one solution that worked, located here.
And lastly, those who always run FS in Administrator mode have had success trying it without Admin mode.