Some mp4 files play while others don’t – encode or file issue?

Hey Kyle,
Thanks for all your support from the previous threads.

Now, just a small issue I’m facing playing video files in mobile (iOS). I’ve got two .mp4 files and for some reason one plays but the other doesn’t. Mind you they both play just fine on desktop it’s just the one mp4 file that doesn’t want to play even after “replace and encode to *all-sizes H.264” is selected.

I’ve tried installing “MP4Box” to see if that did anything to particular mp4 files but didn’t seem to fix it.

Is there any steps that I should take first to help target the problem?

Thanks