1
Close the Store app.
Press the Windows Key + R to open the Run dialog.
In the run box, type this and click OK
wsreset -i
When the Command Prompt window closes, open the Store app and check if that resolves the problem.
2
If that does not resolve the problem, please provide a screenshot of the error you are seeing trying to download the app.
Also, click your Start Button, type winver and press Enter, please provide a screenshot of the resulting dialog.