can’t use face code

Start here:

> Use Face ID on your iPhone or iPad Pro - Apple Support

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

If you have difficulties, try a forced-restart - as this will often clear an isolated software issue:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

If you continue to experience difficulties, you will need to seek assistance directly from from Apple Support.

Official Apple Support

Alternatively, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:

https://apps.apple.com/gb/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to assess your iPad and test FaceID:

Genius Bar Reservation and Apple Support Options - Apple

Hello,

Apple has several documents helping you with Face ID.

This document is specific to seeing a 'disabled' Face ID alert, and explains what to do when you see that notice. --> If an alert says Face ID has been disabled on your iPhone or iPad Pro - Apple Support

If you don't see a 'disabled' message but do have general issues with Face ID not working properly, explore the list of things to try in this document: If Face ID isn't working on your iPhone or iPad Pro - Apple Support

If the first 8 don't solve the issue then use #9, contact Apple.