I see my saved video files on the desktop version. When I click its just color blocks no vid. Ru Pr

I have a Samsung GS21Ultra. I successfully uploaded video footage into Ru and the cloud from my phone. I can edit from there just fine but would rather use a bigger screen for ease. When I log into my desktop version of Ru or Pr it shows the correct thumbnail but when I click on it the footage is just green, red, black. I press play and it shows continuous green/red/blue/gray screen. The files are mp4. I tried uploading just a 10 second file instead of all the files... no luck. I need troubleshooting help! HELP!