It is more likely server hardware limitation. Unless you have a dedicated server with enough processing power to encode videos you are going to have that problem, Last year we quit trying to upload and save videos and started embedding our videos form our Rumble channel and let them use their resources including distribution. Saves resources including processor and storage space. I archive all videos on local machine backups.
I have some ideas but, I'm honestly not sure. We were having problems with our notifications system, saying the module was off but, parts of the module were on and uncontrollable (Emails). The issue seemed to clear up on its own right before we fixed our notifications system.