This error code is usually displayed when windows is unable to determine if you are using a genuine version of Windows. Since, you are getting this error when trying to install an app, I would suggest you try these steps and check:
Method 1: Modern app troubleshooter
This issue could also be caused due to an app error. So, I would suggest you to download and run the Modern app troubleshooter to fix any app errors. You can download it here:
Link Removed
Method 2: Reset store cache and check
If you are unable to install any apps, you can try resetting the store cache and then try to install and check. Refer these steps:
a) Press Windows key +R, type “WSReset” and press enter
b) Check if it takes you to a store page which displays that the cache has been reset
c) Now try to install the app and check.