Face ID setting problem

I’m using iPhone 12 Pro with the newest iOS version . I’ve set up Face ID before and it works for a few months, but suddenly it cannot recognize my face, so I reset the Face ID. When I set up the new Face ID, it keeps saying move iPhone lower/higher. No matter how much I move my phone, it still won’t have any effect and I did restart my phone so many times still getting same thing every time I am setting face id