Firstly, please ensure that the device's memory card is not mounted as an external drive on the computer. Mounting your device as an external disk will leave the game (and probably most of your other apps) unable to run.
Secondly, please try fully rebooting your device and running the game again.
If neither of the above have met with any success, it's possible that some of the game's data may be corrupt - this is especially likely if you have only just installed the game and have never been able to get it to run. If this is the case, please try the following steps.
- Launch the Google Play Store app from your home screen or app drawer.
- Tap the search bar at the top of the screen.
- Type Football Manager 2020 Mobile
- Tap on the installed app.
- Tap Uninstall.
- Tap OK to confirm uninstall.
- From the Google Play Store app.
- Tap Menu followed by My Apps and games followed by Library.
- Tap the app you want to install.
If the game is still not working correctly for you, please get in contact with us via the bugs forum (start your own thread so we can keep track of the issue).