If your iPhone just restarted, enter your passcode once, then lock it and try Face ID again. If it still fails, hold your iPhone upright with your face and the TrueDepth camera uncovered. Check whether the problem affects unlocking the phone or only a particular app.
01Test from the Lock Screen
Section linkWake the screen and look at your iPhone. If the padlock opens, swipe up to get to the Home Screen. If that works but an app still asks for a password, check Settings → Face ID & Passcode → Other Apps and the app’s own sign-in settings. For a failure at the Lock Screen, check that iPhone Unlock is enabled under Face ID & Passcode.
02Remove anything that blocks the scan
Section linkWipe the front camera area and try without a case or screen protector if it overlaps the sensors. Remove sunglasses and test with your eyes, nose and mouth visible. If Face ID works without your mask, check whether your iPhone supports Face ID with a Mask. That feature needs an iPhone 12 or later with iOS 15.4 or later and works with the phone held upright.
03Reset Face ID only if it still fails
Section linkInstall any available iOS update and restart if you haven’t already. Enter your passcode after the restart and test again. If the scan still fails under good conditions, open Settings → Face ID & Passcode, tap Reset Face ID, then Set Up Face ID. This removes your saved face scan; it does not erase your photos or apps. Test unlocking after setup completes.
04If setup fails or you see a warning after repair
Section linkIf Face ID reports a TrueDepth camera problem or cannot complete setup, contact Apple or an authorized service provider. If the phone was recently repaired, check Settings → General → About for Parts and Service History on supported models. If Finish Repair appears next to the front camera, ask the repair provider to check calibration. A working selfie camera does not establish that Face ID is working.