Hello, I'm actually facing the same issue: my app is only accessible to people who subscribed to our service on our website. On this website we've allowed to subscribe with google sign in and we therefore wanted to implement it on our app. However, Apple does not accept a third party sign in solution if its is not implemented ... Although we've added Apple Sign In it does not pass Apple's reviewers (basically in the a similar way as the one you mention)... I'd like to know if there is any updates on that subject or how you've addressed this issue? Thanks