I went on the MS store, click download. Even on a brand fresh install of Windows 10. A specific app will top downloading, and show retry. If you click SEE DETAILS you can see the code

Reporting this problem will help us understand it better. You can wait a bit and try again or restart your device. That may help.
Code: 0x803FB005

SOLUTION:
Very simply,
1. go on the right part on the screen,
2. scroll down until you see SYSTEM REQUIREMENT.
3. It will probably tell you tell you your PC does not meet the minimum requirement. Fix what is missing. And try again.

For me it was a DirectX version not supported from my video card. It could be something else for you.
Same account on a different machine that the System requirement was met. The download went through without any error.