Since it uses the .mp4 container, it is highly compatible with most modern software: Use the Movies & TV app or Windows Media Player. Mac: QuickTime Player supports MP4 natively.

The file might be corrupted or only partially downloaded. Check the file size; if it is only a few KB, it may just be a header or a failed download.

If you found this file in a specific directory or cloud storage, the alphanumeric string is likely a .