Xamarin.iOS RegisteredForRemoteNotifications not called

Points for noticing the big note at the top of the Xamarin guide, a lot of people sometimes gloss over them.

NOTE: The information in this section pertains to iOS 9 and prior, it has been left here to support older iOS versions. For iOS 10 and later, please see the User Notification Framework guide for supporting both Local and Remote Notification on an iOS device.

It would have been nice to see some of your own code sample, but that's neither here nor there.

So as you said you plan on using iOS 10 devices, here is the code we use that works from 10.3 backwards.This code is in our FinishedLaunching() method inside the AppDelegate class.

            if (UIDevice.CurrentDevice.CheckSystemVersion(10, 0))
            {
                // iOS 10 or later
                var authOptions = UNAuthorizationOptions.Alert | UNAuthorizationOptions.Badge | UNAuthorizationOptions.Sound;
                UNUserNotificationCenter.Current.RequestAuthorization(authOptions, (granted, error) =>
                {
                    if (granted)
                    {
                        InvokeOnMainThread(() => {
                            UIApplication.SharedApplication.RegisterForRemoteNotifications();
                        });
                    }
                });

                // For iOS 10 display notification (sent via APNS)
                UNUserNotificationCenter.Current.Delegate = ADSelf;
            }
            else
            {
                // iOS 9 or before
                var allNotificationTypes = UIUserNotificationType.Alert | UIUserNotificationType.Badge | UIUserNotificationType.Sound;
                var settings = UIUserNotificationSettings.GetSettingsForTypes(allNotificationTypes, null);
                UIApplication.SharedApplication.RegisterUserNotificationSettings(settings);
            }

The key really is the following lines:

UIApplication.SharedApplication.RegisterForRemoteNotifications();

OR

UIApplication.SharedApplication.RegisterUserNotificationSettings(settings);

So, after publishing in the AppStore it starts working...

You cannot register the device if it is a simulated device.