Please Check are NUM lock is aktif ? you can press button NUMLOCK fo activated

Hello, The first set of steps from Reset the SMC of your Mac - Apple Support are steps of what to do before resetting the SMC. The next set of steps are for resetting the SMC, which is what to do if the issue you're experiencing persists after following the first steps. Method 1: (for clarity) (1) "Shut down your Mac, if possible. (2) Press and hold the power button for 10 seconds, then release the button. (3) Every Mac has a power button. On laptop computers that have Touch ID, press and hold Touch ID. (4) Wait a few seconds, then press the power button to turn on your Mac. Method 2: (for clarity) If the issue persists, reset the SMC: (1) Shut down your Mac. (2) On your built-in keyboard, press and hold all of the following keys. Your Mac may turn on. (3) Control  on the left-hand side of your keyboard (3.1) Option (Alt)  on the left-hand side of your keyboard (3.2) Shift  on the right-hand side of your keyboard (4) Keep holding all three keys for 7 seconds, then press and hold the power button as well....

Please replace the camera module, many spare parts can be purchased on e-commerce. Link reference : https://www.youtube.com/watch?v=Njx5gcTJ...

The first step to pay attention to 1. Make sure the telephone number in your area is active (registered) 2. Make sure the signal in your area is okay 3. If there is still a problem, please contact the service center