The APP ask for my invitation code, I put it on and then say that it is already used?
@MultiOgre :Sorry I might have misunderstood your initial question.
I'm surprised that you even need to reenter your invitation code, it kind of makes sense that it has been used already, because if I understand correctly the code was originally used by yourself successfully to setup Stadia the first time around.
Isn't there just an option in the app to associate a Google account? I would have thought that that would have been the process rather than trying to register the invitation code a second time.