What is the first step in troubleshooting an iPhone that won’t respond?

When an iPhone is unresponsive, the immediate and most effective approach is to force restart the device. This action is aimed at resolving temporary software glitches that may prevent the phone from responding to inputs. A force restart essentially cuts power to the device and forces it to reboot, providing a fresh start that can often resolve issues without further intervention.

While replacing the battery, resetting the device, or checking for physical damage may be necessary in some scenarios, these actions generally come after trying the simple yet effective method of a force restart. If the device is not responding, starting with a force restart is a standard troubleshooting step, as it requires no tools and can quickly determine whether the problem lies with software rather than hardware or other components.