Apple Sign in - get email

I'm using Unity's SignInwIthApple, and it seems to log in fine on mobile so far so great
The problem is that I want to take the user's email or some sort of identification in order to save them in my database, but when I try this-
args.userInfo.email - I get an empty string.
If I try args.userInfo.idToken I get a long token, which means args.userInfo is not null, but why doesn't it contain the email? is there another way to get email or userID from apple users?
args.credentialState returns "Revoked"

Here it the function and I try to extract user information after the successful login, it's the default script from the apple sign in asset-
private static void LoginCompletedCallback(int result, [MarshalAs(UnmanagedType.Struct)]UserInfo info)
{

var args = new CallbackArgs();
if (result != 0)
{
args.userInfo = new UserInfo
{
idToken = info.idToken,
displayName = info.displayName,
email = info.email,
userId = info.userId,
userDetectionStatus = info.userDetectionStatus


};
Debug.Log("args.userInfo.email);
Debug.Log("2args.userInfo=" + args.userInfo.idToken);

 

have a same problem, displayName alse is a empty string. is it also opt?

 

Why don't you use the info.userId field?

 

Can you explain me how do I opt in for email ?