Check for updates: Make sure your iPhone is running the latest version of iOS
Check your Face ID settings: Go to Settings > Face ID & Passcode to make sure Face ID is set up and the features you want to use are turned on
Check the TrueDepth camera: Make sure nothing is covering the camera, like a case, screen protector, or smudge
Check your face: Make sure your eyes, nose, and mouth are visible to the camera
Restart your device: Restart your iPhone and try using Face ID again
Add an alternate appearance: Go to Settings > Face ID & Passcode > Set Up an Alternate Appearance
Reset Face ID: You can try resetting Face ID
This video may also help you learn how to reset Face ID on your iPhone:
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