I made a 1 minute video in iMovie on my macbook with footage shot on a gopro and an iPhone 7. All of the individual videos playback on iPhone. I uploaded my movie to youtube and it worked HD. I am running into a problem when I save to file and then try to move it to my iPhone (tried iCloud drive and One Drive). The error I get is a grey screen with the QT Q on it. I DO get audio. I'm using iMovie 10.6.1. What is going on!! Any help is appreciated! BTW I'm trying to get this HD video uploaded to Instagram, so if there's a workaround where I don't need the video on my phone, that would solve my problem too. Thanks guys!