In earlier versions of tvOS 13 I could use ASAuthorizationPasswordProvider to allow users to login with their existing keychain credentials like this:
let request = ASAuthorizationPasswordProvider().createRequest()
let authorizationController = ASAuthorizationController(authorizationRequests: [request])
I was using ASAuthorizationPasswordProvider without ASAuthorizationAppleIDProvider.
But since a couple of tvOS 13.x updates, this stopped working.
The ASAuthorizationControllerDelegate is always called with `authorizationController(controller: ASAuthorizationController, didCompleteWithError error: Error)` and `ASAuthorizationError.Code.unknown`.
On the device an alert is shown with the message "account not supported" "your apple id cannot be used to create accounts for other apps."
I tried it with different Apple IDs.
The same code is working fine on iOS.