Video slow stuttering buffer

Hello, I allowing video upload on my auction site but i am having buffering problems when playing on pc and my mobile. I am just wondering how I can fix this or help the video load faster and smoother. Will uploading a lower video resolution help or is there something i can do to my server settings to load faster and smoother?

Here is the url: https://cyberdealerz.com/listing/black-n-decker-hedge-trimmer-16/