topic title. these are the only allowed filetypes right? so why are they being rejected all of a sudden?

webm and webp are not allowed

Okay but they still rejected the mp4

are you uploading the mp4 in the upload video section?

Or maybe is just to big of a file

Either you're not using the "upload video" tab found here realbooru.com/index.php?page=post&s=addVideo
Or you haven't posted enough non-video images to unlock permissions. I don't know how many you have to post but try doing that.

forum #6951 by the way this thread exists already for these kinds of questions.