If you click on the screen twice with a using three fingers and it doesn't work for you, force restart the steps:
That is how you do a “hard reset”. See below:
Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:
- Press and quickly release Volume UP button
- Press and quickly release Volume DOWN button
- Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF).