There will be some cases that while playing Overwatch on an Xbox One, Windows 10, you got this error 0x803f8001. It even happens when you start the game.
Some Insiders said that they have tried many method to bypass the issue, such as: uninstall & then re-install, do a hard reset or sign in & sign out the Microsoft account.

In fact, those methods does not always solve the problem. If you’re lucky, it’s fixed.
Our experts from Windows10Insider.com have investigated & found that the issue might occur, if the game is not updated properly. So, to fix it, please follow these steps below.

Fix the issue 0x803f8001 of Windows Store while playing game

1. Go to Countdown for Overwatch on Windows Store
In the Windows Store app, on the menu in the upper right, select Downloads and updates.

2. On the download page, select Check for updates.

Please note that this method does not only fix for Overwatch but also for GTA V (Grand Theft Auto 5) on Xbox One (Windows 10).
If you have another solution, please share it in the comment section below.
Thank you!