MP4 (h264) to play on an iPad?

So I cant get a RH Responsive HTML5 project to play an MP4 on an ipad?  but works fine on a pc (tested 3 w/browsers).
Outside the published project, the iPad plays Mp4's without any problems.
But within a RH Responsive HTML5 project on the ipad, the MP4 shows up as a black square with a "crossed out" play button in the middle.
on any pc the published RH project, plays fine.

I've tried several different mp4's (h264) ,,, I've even multiple sizes of MP4s.

Am I missing something?