Can't trim recordings

I use MCEBuddy to trim recordings I have made with PlayON. For some reason when I try to trim recorded youtube videos MCEBuddy does nothing. I click add and select the file, then nothing. They are MP4 files. I don’t know whats going on.

Changed the name of the file to 1 with no extension while I was trying everything I could think of. It worked. So weird.