IMovie 2019 not sharing movie?

I made a music video and it has lots of green screen/ picture in picture if that makes a difference, it won't share at all, I can't even share it as a file to desktop it says "successfully shares to iTunes" but it's not in iTunes, I can't get it to hate to YouTube either, any solutions?

How big is it?
video can get pretty big, and there's a limit for uploading.
try rendering it in a slightly lower quality. What codec/file type are you exporting to?