Why can't I install amazon prime app on my Xbox

Check if there is a new update for the Amazon Prime App, which you haven't installed yet. If there is no one, try to delete the app and to install it once again.

I fixed the problem. I solved again all of my app, games on my external storage except Amazon prime. And then you have to reboot your Xbox in the settings. Click on delete everything. So that nothing is more saved on it. Then restart, download the update
and then download prime video again. On my Xbox the prime app is now working !

Amazon Instant Video shows any films purchased through Amazon and any Amazon Prime content.

Xbox doesn't have a Prime App, rather Xbox Video which only shows films and shows purchased through Xbox Store.

If films/shows purchased from Amazon aren't showing in Amazon Instant Video app you will need to contact Amazon Customer Support to verify your purchases.

Remember, Amazon Prime content changes so they remove films/shows periodically and add new ones. Amazon Instant Video purchases remain all the time.

I managed to install the Amazon prime video launcher.And any other free game from the Microsoft store.I have tried to install the Xbox installer app through the Microsoft store;but that won't install either?This flight sim 2020 doesn't want to know my Pc?I have nearly all the other flight Sims running on windows 10 older games running with patches.Why can't Microsoft give me access to the game?😩

Microsoft has no control over the Amazon Prime App. Everything presented to you once you launch Amazon is entirely up to Amazon.

There is one section called "Library" I believe that holds movies/shows you purchased separate from the "free" prime movies. Do you not see that on the Home Page of the Amazon App? I purchased the Star Wars Digital Bundle and I still see them on my Amazon
App so I know it works correctly.