Can't upload videos from iMovie to H5P

Hi,

I'm trying to upload a video that I made using iMovie. I have a MacBook and exported the video from iMovie to finder, documents. Then I tried to do a interactive video and upload it so that I could edit, but it can't upload it. And it's not the length... I've tried with a 4 second video too so it can't be the size. I can upload normal videos that I haven't edited, in iMovie, from the same folder. I think it's the format somehow, does anyone know anything more about what formats you can and can't use with H5P.

Thank you in advance!