Why is my Face ID not working again when I have already updated my phone to the latest IOS.

Hello ayanniyi128,

Thank you for using Apple Support Communities. If your Face ID is prompting you of an issue, we can help out by recommending some steps to troubleshoot it. To start off, follow the steps listed here: If Face ID isn't working on your iPhone or iPad Pro - Apple Support

1.) Check for updates: Update your iPhone or iPad to the latest version of iOS or iPadOS. And make sure that your iPhone or iPad model supports Face ID.

2.) Check your Face ID settings: To check your Face ID settings, go to Settings, then tap Face ID & Passcode. Make sure that Face ID is set up and that the features you're trying to use Face ID with are turned on.

3.) Check that nothing is covering the TrueDepth camera: Remove anything that might be covering the TrueDepth camera like a smudge, case, or screen protector.If you're using iPad in landscape orientation, make sure that your finger or palm isn't covering the TrueDepth camera. If it is, an alert might appear at the top of the screen that says "Camera covered" with an arrow pointing at the TrueDepth camera.

4.) Make sure that your eyes, nose, and mouth are fully visible to the TrueDepth camera. By default, Face ID doesn't work if anything is covering your mouth and nose. If you're wearing a face mask and have already set up Face ID with a mask.

5.) Restart your iPhone - Apple Support

6.) Reset Face ID. If you still need help, reset Face ID, then set it up again. Go to Settings, tap Face ID & Passcode, then tap Reset Face ID

If these steps don't help you, please reach out to Apple Support. They might have to evaluate your device. Use this link to reach them: Get Support

Thank you for using Apple Support Communities. Take care.