Unable to import mp4 to iphone

I used Photos app to import all the videos and photos from iphone, and organise them into albums

After importing from iphone to Photos App, I want sync specific video albums back to iphone.

When I try to sync (via Finder), i get..

> Some videos, including “E3983046-9FB8-4CA4-9D93-5D0088795907.mp4”, were not copied to the iPhone “Iphone T.” because they cannot be played on this iPhone.

I am 100% sure those videos were playable on the iphone before importing. They are also playable in the Photos app.