Face ID

My iPhone XR Face ID was working perfectly before yesterday. It wasn’t allowing me to use my Face ID anymore to unlock the phone. I restarted my phone various times in hopes it would work but it didn’t. I reset my Face ID and tried to set it up. I’m set up it says to move phone a little lower or move phone a little higher. Afterwards it tells me Face ID isn’t available right now. Does anyone know how to fix this?