So, here's how to force an iPhone X to restart.
- Quickly press and release the Volume Up button.
- Then, quickly press and release the Volume Down button.
- Finally, hold down the Side button until you see the Apple logo on the screen.
If the smartphone becomes stuck on a black screen due to software problems, you should press the Side button for roughly 20 to 30 seconds.
If a hard restart can fix your iPhone, it signifies that it was turned on the entire time, but the software has crashed, leaving it with a black screen and no response. This state is nearly indistinguishable from that of an iPhone that has been switched off.