I have developed an iOS app that allows users to login via their Google Account using OAuth.
It was rejected by Apple for allegedly violating 11.13 of the App Store Review Guidelines:
11.13 Apps that link to external mechanisms for purchases or subscriptions to be used in the app, such as a “buy" button that goes to a web site to purchase a digital book, will be rejected
Upon asking for more information, Apple said:
To clarify, your app has been rejected for including means for users to acquire new Google accounts. Linking customers to a page where users may sign up or register new accounts, and then use those accounts to purchase service/server space to be used within the app, is not appropriate and must be removed before resubmitting your app.
Here's a screenshot of the infringing functionality:

The Gmail iOS app has the same screen and I can't find any other app that connects to Google by OAuth so I'm at a loss on how to fix this.
Any ideas?
Many thanks!
EDIT: Here's a screenshot of same offending screen in Gmail
