Windows 10: Microsoft Store on Windows 10 will not let me install anything; User authentication error?

In May of last year I suffered a main HDD failure and then, long story short, my life sort of fell apart and I couldn't really get around to replacing the HDD and reinstalling Windows until about September, and then I couldn't actually work on restoring the PC until just this week. While setting things back up, I opened the Microsoft Store and went to reinstall some games -- Minecraft, Forza Horizon 4, etc. Instead, I got a very vague"Something went wrong on our end. Try again later."I waited, still nothing. Noticed Windows 10 had a pending update 21H2, so I went ahead and applied that. Stil

:)

 

Windows 10 Tweaks

As you may already know, Windows 10 (as well as Windows 8) allow you to log in with a valid Microsoft account, instead of creating a local account that only works on your machine. However, you may prefer to keep a local account for privacy reasons. If you do, though, some Windows 10 features—like Cortana—may not work. Despite the default behavior, the Windows 10 Store is not one of them. You can still log in to your Microsoft account for just the Store without switching to a full Microsoft account. The process, however, is not terribly obvious. To do so, follow these steps:

• Launch the Store from your Start menu.
• Click the user icon next to the search box.
• Click “Sign-in” from the menu that appears.
• Choose “Microsoft account” and log in like normal.
• When the “Make it yours” box appears do not enter your password. Instead, click “Sign in to just this app instead.”

from Lifehacker

 

Microsoft Account authentication

After more research, I have found my answer. It looks like the issue was that Microsoft released a new Microsoft Authenticator app with the features first introduced in Microsoft Authenticator Beta. The new app received a prompt to approve access to my Microsoft
Account when signing on from a new PC, though I find it strange that the beta app wasn't directly upgraded to the new version of the app.

Microsoft now has three 2 step authentication apps available in the store for Windows 10 Mobile:

• Authenticator - original app from Windows Phone 8
• Microsoft Authenticator Beta - originally released to Windows 10 users when Windows 10 Mobile was only available on the Windows Insider program.
• Microsoft Authenticator - the official Windows 10 app no longer in beta

 

Microsoft Authenticator (beta) app in Store

Source: Microsoft Authenticator (beta)