The recent changes in the latest iOS version may have caused the Messenger app to become a little glitchy in its initial run, so try quitting and restarting it. It may happen to any programme, especially if you're using a new platform, and deleting the app can assist. Here's how you do it:

1. Swipe up from the bottom of your screen to the middle and keep it there until the App Switcher displays.
2. Swipe left or right to find Messenger in the list of applications.
3. Touch and hold the Messenger app firmly.
4. Then, to clear the app hit the Minus (-) sign/icon.
5. Alternatively, as soon as you see the negative symbol, swipe up to quit the Messenger app.