As of April 2020, I believe Sign In With Apple must be an option for social apps. This requires the user sets up Two Factor Authentication (e.g. Face Id) on their device.
If the Apple Id account is an under 13 child account created through Family Sharing, the user cannot completely set up 2FA, although it can be switched on, but never switched off.
For example:
- I create a child account via Family Sharing on my device, then log out and log back into my device using that child account.
- I go to an app that uses Sign In With Apple and attempt to sign in. It shows the following message "Two-Factor Authentication Required".
- I then follow the dialogs to set up 2FA, at some point in the flow I hit this error message: "This Feature Cannot be Set Up". I cannot add 2FA to my child account.
- However I can go into Settings and switch it on, but I can't set up face or touch id. But ok, I'll just try and sign into that app again
- When I try Sign In With Apple after (partially) enabling 2FA, I see this error: "Cannot Create Account. Your Apple ID cannot be used to create accounts for other apps"
So there it ends, as a <13 child account I can neither set up or use 2FA for signing into apps.
Is this inability to set up 2FA due to COPPA?
Could this be circumvented simply by using their email / password to sign in?
If could this please be surfaced more clearly in the documentation. It took a good few days of testing to discover the edges of this feature and is confusing for both developers and parents alike.
