iPhone 12 Pro Max - mp4 not supported

Hi all,

Please help! I’m a content creator- I have always recorded on my iPhone, airdrop media to MacBook, edit in premiere pro then export the complete mp4 file back to my iPhone via airdrop. The file works on every other iPhone I airdrop it to except the 12.

I purposely purchased this phone for content creation so I’m very frustrated, I would appreciate any help!

Thank you so much!