Hello Federico,
that's not an error and you have not mistakes.
That's a message informing you that you are using the default Google Application built in the component.
If you hovered that label you would get the detailed explanation:
QUOTE:
Non hai impostato le credenziali per la tua Google app per Analytics e stai usando il nostro account predefinito gratuito di Google app per recuperare i dati statistici....
Creating your Google app is not mandatory, so you can use the default Google app without any difference.
Best regards