Adding MP4 File to slide - Plays when building, White screen when preview or publish

Hi Scott,

Thanks for reaching out!

I was able to replicate the behavior on my end as well. It looks like the issue is isolated to the video in your slide, because replacing your video with a different one allowed the video to play without any issues. Here's a sample link for your reference.  

I then used a tool called Handbrake to re-encode your video, and this seems to have corrected the behavior indicating the the issue was with how your video was encoded. Here's another link to your course with a re-encoded version of your video, where I can confirm that it plays properly. Try re-encoding the video on your end, and let me know if this works for you!