Google has recently updated Google Play Games to version 2, changing how players log in or change their accounts.
Previously, you could choose or switch accounts freely while playing Massive Warfare.
Now, Google Play Games 2 automatically logs you in when you launch the game — and you can’t switch accounts during that session.
This behavior is now similar to Steam or Apple Game Center.

Remember that Massive Warfare is designed for one single account per player.
If Google Play Games logs you into the wrong or a new account, you won’t be able to switch it from inside the game.

Here’s what to do:

1. Exit the game completely.
2. On your Android device, press and hold the Massive Warfare icon.
3. Tap “Choose Profile.”
4. Select the correct profile that matches your game account.
5. Once selected, open the game again to access the right account.

If you don’t see the “Choose Profile” option when pressing the game icon, you can also change your Google Play Games account directly through your device settings:

• Go to your device Settings → Google Play Games → Set my account, and choose the correct account you want to use.
  
     

For more details, check the official Google support page here:
🔗 https://support.google.com/googleplay/answer/14754238