Face ID

So when I first go my iPhone the Face ID worked fine but the after a few days it stoped working. Then when I went into settings to re add my face it would never set and would say “move iPhone higher or move iPhone lower ” endless.I have tried everything from restarting my iPhone, update it to the newest version, cleaned my Lens, took of my screen protection, checked the ID cam, also the green light on the right top corner still shows so i know it works. But it still says “move iPhone higher and move iPhone lower ” ENDLESSLY!!! Please help me