Hello, my MacBook Air has been shutting down unexpectedly from time to time when I wake it up using the fingerprint button. What should I do to fix it?

Is this happening also when the Mac is booted in the safe mode?

If this is not happening in the safe mode it is most likely happening due to an external piece of software

Start up your Mac with Apple silicon in safe mode

1. On your Mac, choose Apple menu  > Shut Down.
2. Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.
3. Press and hold the power button on your Mac until “Loading startup options” appears.
4. Select a volume.
5. Press and hold the Shift key, then click Continue in Safe Mode.
6. The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.

Start up your Intel-based Mac in safe mode

1. Turn on or restart your Mac, then immediately press and hold the Shift key until you see the login window.
2. Log in to your Mac.
3. You might be asked to log in again.
4. On either the first or second login window, you should see “Safe Boot” in the menu bar.

Do you have a M2 MacBook Air? If so, this can be a known problem with hardware failure I am afraid. If the issues persist please Contact - Official Apple Support to set up hardware service for your device