This means that the Game Center is not activated on your device. Follow these steps to complete the process successfully:
- Go to your device settings.
- Scroll down until you reach the (Game Center) then click on it and activate it by making the button next to it green.
- Click "Continue" and enter this account data.
- Now, you will be able to change the account.
- Go to your device settings.
- Scroll down until you reach the (Game Center) then click on it and activate it by making the button next to it green.
- Click "Continue" and enter this account data.
- Now, you will be able to change the account.