Uploading videos like that require FFMPEG to process. So I would check a couple things here. 

Go into Studio > Dashboard 

Under the Site Setup, check the Cron Jobs area to make sure you see the cron jobs listed there and also check the "Last cron jobs execution" to see if it matches when you try to upload the video. 

Also under Site Setup, there is a "Click Here" link to to find out if permissions are correct . Click that and make sure your FFMPEG is executable.