Turn your device on and off, and perform a soft reset.
INSTRUCTIONS & INFO
To turn off iPhone, press and hold the Sleep/Wake button until the slider appears then select and drag the Power icon to the right.
To turn iPhone on, press and hold the Sleep/Wake button until the Apple logo appears.
To unlock iPhone, press either the Sleep/Wake or Home button, then press the Home button again. To lock iPhone, press the Sleep/Wake button.
Note: iPhone locks automatically if you don't touch the screen for a minute or so. To adjust the timing, from the home screen select the Settings app > scroll to and select Display & Brightness > select Auto-Lock > desired time. To set a passcode lock, from the home screen select the Settings app > scroll to and select Touch ID & Password.
If your device stops responding, you can reset it by pressing and holding both the Sleep/Wake and Home buttons for at least ten seconds, until the Apple logo appears.
Note: If your device remains unresponsive or does not turn on, click hereto learn what to do.