Captivate 8 - Videos not working in published format

Prior to a lot of conversion to mp4, videos used as event videos worked fine in our modules, now all of our videos are visible in preview but will not play in published format to browser.  The event video player shows, but we get a continuous rolling wheel.  I have tried various browsers, re-conversion of video files, but cannot get them to work.  Any thoughts would be greatly appreciated.