If your iPhone or certain applications become unresponsive after installing a new iOS update, restarting the app and the device system should resolve the issue. It's possible that the new modifications were not correctly applied, causing the Messenger app and other services to break. In such a situation, use these instructions to force the Messenger app to shut and then restart your iPhone 7 Plus:

• Quickly press the Home button twice. A list of recently used applications will appear on the screen as a result of this action.
• To close the Messenger app preview, swipe upon it.
• Close any other programs that are running in the background in the same way.

To refresh the system and internal memory, execute a soft reset or reboot your iPhone after removing recent applications.

• Press and hold the Power button until the Slide to Power off prompt comes on the screen to restart your iPhone. To totally turn off your gadget, drag the slider. Press and hold the Power button for 30 seconds, or until the Apple logo appears.