AFF Adult Friend Finder website, My Shotcut vids don't play

I am in the AFF website. I have made videos of me cooking a steak and me working out with my rings. After adjusting the video with ShotCut, AFF says the audio plays but not the video. I my videos normally play everywhere just fine.

I have played my videos in the following places:
YouTube
VLC
Firefox
Chrome
Whatever that Microsoft default player is called

Seems to work everywhere as an MP4.

Any ideas?

In the export panel try to use the Youtube preset, I’m thinking maybe they are very strict with either GOP/b-frames or codec.
Try to find if there’s a document on their website with the recommended settings for videos.