Can't get mp4 to work on a site

I feel your pain. After a few bad experiences, I decided not to get involved with anything involving Windows hosting. (Windows hosting may be fine for what it does, but all the tips and tricks etc. that I’ve learned over the years apply to Apache, and I just can’t be bothered messing with an alien system that has a far smaller user base.)

Is this useful to you? http://www.firecoresoft.com/convert-mp4/convert-mp4-to-webm.html
if it is your video problem, you can have a try to convert mp4 video to html 5 video.