I would first recommend closing any open applications in multitasking and restarting the device. If unfamiliar with multitasking, I have included a screenshot on how to process an application close. Test the results after processing this step.
If an app is unresponsive but the system seems to respond to button presses, you can force the app to close:
- Double-click the Home button.
- Swipe left or right until you have located the app you wish to close.
- Swipe the app up to close it.
If the issue persists, see the article below.