Unable to set up face ID

When i click on set up face ID, it starts setting up the face dimensions (without curvy square brackets) and keeps asking to move my iphone a bit lower/higher all the time. I’ve tried positioning it the best and tried all positions (zoomed in and out) at a proper distance and even in different light medium but it just wouldn’t focus on my face to get through and set up my face ID. I literally tried every position and still it says to move the iphone higher or lower and then this page appears. What do i do?