What is your end goal (watching it, editing it, or fixing a software error)?
The double extension .mp4.mp4 often happens when a file is renamed automatically or downloaded through a script. Try renaming the file to just video.mp4 . 5e73c93e3bfd7d7bf07cf_source.mp4.mp4
Ensure you haven't manually renamed it. The software is looking for that exact string of characters. What is your end goal (watching it, editing