1
There are usually two versions of the Media player installed in Windows, the old Legacy Windows Media Player and the new Player app, have you tried playing the video file in both of those apps, and if so, do you see the same error?
Is this problem only occurring with one video file or all video files?
2
If the problem is only occurring with one video file, that may be encoded in a format the media player cannot play, right click that file, and select Properties, please provide a screenshot of the resulting properties dialog box.
3
If this problem is occurring with all video files, open the Settings App.
Go to Apps - Installed Apps.
Scroll down to find the new Media Player app and select it, then click 'Advanced Options.
Perform the Repair option and the Reset option on that app.
Then try playing a video file to test if the app is then working correctly.