Can't get email from authenticated user with Facebook
<p>I am using Firebase's Facebook Login to authenticate my users. I had to upgrade my project to Firebase 3.x thus I had to change this bit. I achieved getting 'fullname' with <code>user!.displayName</code> and 'photoUrl' with <code>user!.photoUrl</code>for example; but cannot access email with <code>user!.email</code> even though 'email' scope is set.</p>

<pre><code>@IBAction func facebookLoginDidTouch(sender: AnyObject) {
let facebookLogin = FBSDKLoginManager()

facebookLogin.logInWithReadPermissions(["public_profile", "email"], fromViewController: self, handler: {
    (facebookResult, facebookError) -&gt; Void in
    if facebookError != nil {
        print("Facebook login failed. Error \(facebookError)")
    } else if facebookResult.isCancelled {
        print("Facebook login was cancelled.")
    } else {
        let credential = FIRFacebookAuthProvider.credentialWithAccessToken(FBSDKAccessToken.currentAccessToken().tokenString)

        FIRAuth.auth()?.signInWithCredential(credential) { (user, error) in
            if error != nil {
                print("Login failed. \(error)")
            } else {
                print("Logged in!")
                print(user!.displayName) // works
                print(user!.photoUrl)    // works
                print(user!.email)       // returns nil
            }
        })
    }
</code></pre>

<p>I am pretty sure the email is valid because it used to fetch the email just fine before I upgraded to Firebase 3.x. I also tried multiple Facebook accounts but no luck. What may be the problem?</p>