Your question is not about Lightroom Classic, but you have posted in the Lightroom Classic forum. You want to post it in the proper forum, which is the Lightroom (Ecosystem) forum.
Are you using Lightroom (Lr icon) or Lightroom Classic (LrC icon)? What version NUMBER? We need the version NUMBER and not words like “latest” or “up-to-date”.
What is your operating system and version NUMBER?
Where are you looking that you cannot see a video file? Can you include a screen capture of where you don’t see this expected video file? What type of video file is it: MP4, MOV, AVI, other?
Find the Lr app and version in attachment. I use external device SanDisk SSD c type to connect. Lr app isn't showing any of my MP4 videos when trying to import. It just lists jpg images. Also attaching preference option screen.