Face ID bug

I have a problem setting up the Face ID on iPhone X.

I have tried to restart it a few times and also reset and erased everything for a new user but still it doesn’t work.

Whenever I try to set up Face ID it opens the front camera where I have to position my face in the frame. When I do it it says “move iPhone a little lower” or “move iPhone a little higher”. I move it but nothing changes. How can I fix that?

I already have the latest iOS update.