If you're experiencing technical issues due to connection or other device issues, you might want to restart the app and reopen it again. Here's what to do:

iPhone 8 and lower:
1. Double click the 'Home' button to see all the apps that are currently running.
2. Scroll through until you find GoP3, press and hold your finger against the app until an 'X' appears on the icon.
3. Click on the 'X' to closes the app. Press the home button to return to your home screen if your phone.

iPhone X and higher:
1. Swipe up from the bottom of the screen and pause while still pressing the screen
2. Find GoP3 and swipe the window up to close the app.
3. Swipe up from the bottom of the screen again to return to the home screen of your phone.

Android
When the game does not want to close the usual way you can try the following
  1. Open the Settings of your phone.
  2. Choose Apps.
  3. Touch the Running tab to view only active or running apps.
  4. Choose the app that's causing you distress.
  5. Tap the Stop or Force Stop button.