Unity Banner Ads appear very small when i choose IphoneX but now when i Choose freeAspect!

Hey Guys,
Im just adding AdBanner for the first time to a game. When I set the Game Preview to for example Iphone X the Banner appears very very small… When I change it to FreeAspect it looks fine.

Do I have to change anything in the code? Is the preview just wrong? Will it looks different when its finally build to IOS?

I also have this problem