Face ID is not working on my iPhone 13 Pro Max

There might be something wrong with the face ID sensor requiring service.

Make sure you have done all the steps in:

If Face ID isn't working on your iPhone or iPad Pro - Apple Support

Last step:

Get service

If you still can't enroll your face, contact Apple Support.

This article migth also be relevant

If an alert says Face ID has been disabled on your iPhone or iPad Pro - Apple Support

What to do next

1. Update your iPhone or iPad to the latest version of iOS or iPadOS.

2. If you still can't enroll your face or unlock your device with Face ID, take your device to an Apple Store or Apple Authorized Service Provider, or contact Apple Support about your iPhone or your iPad.

Good Luck!