After reset my Face ID stops

See Set up Face ID on iPhone https://support.apple.com/guide/iphone/set-up-face-id-iph6d162927a/ios

And see If Face ID isn't working on your iPhone or iPad Pro https://support.apple.com/en-us/HT208114

If after following the first seven steps given, "... you still need help, reset Face ID, then set it up again. Go to Settings > Face ID & Passcode and tap Reset Face ID. Then tap Set up Face ID to set it up again. 

If you can’t enroll your face, take your device to an Apple Retail Store or Apple Authorized Service Provider or contact Apple Support." You'll need to contact Apple Support at this time unless an Apple Store is open in your area.

You need to take it to an Apple Store or Apple Authorized Repair Store.

Genius Bar Reservation US.    

Authorized Service Provider.    

You need to take it to an Apple Store or Apple Authorized Repair Store.

Genius Bar Reservation US.    

Authorized Service Provider.    

I have the same issue when I contacted support they told me it had to be fixed by someone and the cost would be $550 I am seriously in shock since everything works on my phone except for this and its the same thing Higher or lower but it wont register my face. I bought my husband an iPhone 11 because he couldn’t send in his phone due to Covid 19 that was $1000 and they returned the phone because it was “face ID unavailable” so no trade in discount. So i don’t know if it would be worth it to you to try to get it fixed thru them. My phone is out of warranty if its in warranty maybe they will help you. I always advocated Apple because of their Customer Service I had to repair my husbands phone 3 times in the last 7 years but they were always reasonable. This price is outrageous!

See if anything here helps.

Face ID on your iPhone or iPad Pro.   

Face ID on your iPhone X - Get help with   

Face ID not working

Face ID not working' problems on iPhone

Fix iPhone X Face ID Not Working

Face ID Not Working

I live 2.5 hours from a store. Customer care said it would cost over 1000 to send in phone and get a replacement. Everything works on phone except face id which just started after I upgraded to IOS 14 on Iphone X.

Both high and lower

Yes

Open my lock notes with Face ID

Open my locks notice with Face ID

Same happened to me. I can’t believe that after paying &1,200 for an iPhone X this seems to be a common problem.

not working please help me

Right I kept thinking how can the repair be half the price of the phone?!?!