I have come across this problem every time Microsoft release one of their bigger “update”. I go to open say “Redbull TV” click on a video and normally get a generic “playback failed” error.
This happens because i’m running a “N” or “KN” version of windows which I believe doesn’t ship with media stuff because Microsoft got told they shouldn’t in Europe. Sadly to fix it you have to download a “Media pack” after each update. A really useful link can be found here:
This lists which “Media pack” you will need for your version of Windows. Proceed to download and install the one that relates to you (installing one for a older Windows version will feel like it has installed but playback will still not work) and you should now have video playback in Store Apps.
To find out your “version” on Windows 10 go to Settings > About.
This is a nasty issue for users as the errors are useless, Microsoft keep releasing updates that remove the media pack forcing the user to re-download it again and worst of all it shouldn’t even be a thing! I hate to say it but you don’t have to jump through these hoops on iOS or Android.
Hope this helps, any questions just leave a comment.