The new yudofu website is being worked on and hopefully will be released to the public as soon as possible and all of these issues should be fixed, but before that please respond to my questions below.
First i would like to know if you have tried to use any other sites to host the videos, e.g. kissanime.to. Also make sure you are using the direct link from the video ("Copy video URL")
Second, what browser are you using? are there any plugins that could conflict with the playback of the video.
Third, how long have you had this issue for?