Restart your iPhone

Learn how to turn your iPhone off, und dann wieder auf.

So starten Sie Ihr iPhone X neu, iPhone11, iPhone12, iPhone13, iPhone14,iPhone15

1. Press and hold either volume button and the side button until the power-off slider appears.
   
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.

How to restart your iPhone 6, 7, 8, oder se (2ND oder 3. Generation)

1. Press and hold the side button until the power-off slider appears.
   
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the side button until you see the Apple logo.

So starten Sie Ihr iPhone SE neu (1ST -Generation), 5, or earlier

1. Press and hold the top button until the power-off slider appears.
   
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the top button until you see the Apple logo.

If your reset is still unsuccessful refer to the official iPhone guide

https://support.apple.com/en-gb/HT201559

Maybe your iPhone needs some awesome phone cases!