m0useanswered grow question 6 months ago I use a program called Open Shot video editor for my vids. I convert them all to MP4 with the setting FHD 1080p h,264 encoding and they seems to work fine for me.
The app is a little buddy sometimes but works fine for general converting, small learning curve for it. also reduceing your videos size helps a lot. less data less options for it to be corrupted or error out.
Could try that or just try uploading during off hours so the server has more time to process it.
The sites buggy as fuck, as all the others have said. just gotta roll with the punches.
Good Luck!