How can I fix a malfunctioning fingerprint or face ID scanner on my mobile device?

1. Check the device manufacturer's official website for recommended troubleshooting steps.
2. Check if the settings for the scanner have been enabled and configured correctly.
3. Restart the device.
4. Clean the fingerprint/face ID scanner.
5. Try using a different finger/face.
6. Reset the authentication settings and try setting up the scanner again.