If ScreenCoach is not running in the background, then when it stops running, the child will get 2 more minutes of app usage before all of the apps are blocked, even if they try rebooting the device.
For this to happen, ensure all permissions and, most importantly, "App Blocking" are granted on that device. You can check 'how' here.
If you are testing this, you will need to open any app for 2 minutes to start counting!
How to test blocking:
1. Kill the ScreenCoach app (meaning remove it from the background) on the kid's iOS device.
2. Start using any other app (not ScreenCoach) on the same device.
3. Wait and use the app for around 2 minutes. Do not screen lock the device.
4. The app and all other apps (except Always Allowed apps) will be blocked after 2-minute usage.
You will see this screen:
In order to unblock:
Bring the ScreenCoach app to the foreground by reopening it.