Tiktok crops my pictures and videos

Whenever I post something, tiktok ends up cropping my posts which end up with black bars on the top and on the buttom. I set the screen ratio to 9:16 and it still ends up the same.

I make gaming content and record all my stuff on pc. Does it have something to do with that? How do I get a full screen, cause I feel it's looks dumb and prevents me from getting more viewers and likes :(