azure notification issue: apns works while template not response - xamarin.forms

Question

Follow this tutorial "Add push notifications to your Xamarin.Forms app" for Xamarin.Forms development. After insert notification code in Azure backend and iOS, the notification template send out but no alert on device. However, the test sending of APNS shows the alert on the device. Appreciate any suggestion.
Here is my RegisteredForRemoteNotifications
public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
const string templateBodyAPNS = "{\"aps\":{\"alert\":\"$(message)\"}}";
JObject templates = new JObject();
templates["genericMessage"] = new JObject
{
{"body", templateBodyAPNS}
};
/*
// Register for push with your mobile app
Push push = TodoItemManager.DefaultManager.CurrentClient.GetPush();
try
{
push.RegisterAsync(deviceToken, templates);
}
catch (System.Exception ex)
{
Debug.WriteLine(#"Register error: {0}", ex.Message);
}
*/
Hub = new SBNotificationHub(Constants.ConnectionString, Constants.NotificationHubName);
Hub.UnregisterAllAsync(deviceToken, (error) => {
if (error != null)
{
Console.WriteLine("Error calling Unregister: {0}", error.ToString());
return;
}
NSSet tags = new NSSet(); // create tags if you want
var expire = DateTime.Now.AddDays(90).ToString(); // set expire
try
{
//register native notification
Hub.RegisterNativeAsync(deviceToken, tags, (errorCallback) =>
{
if (errorCallback != null)
Console.WriteLine("RegisterNativeAsync error: " + errorCallback.ToString());
});
//register template notification
Hub.RegisterTemplateAsync(deviceToken, "add_newbook_notification", templateBodyAPNS, expire, tags, (errorCallback) => {
if (errorCallback != null)
Console.WriteLine("RegisterNativeAsync error: " + errorCallback.ToString());
});
}
catch (System.Exception ex)
{
Debug.WriteLine(#"Register error: {0}", ex.Message);
}
});
}
Because there could be multiple notification registration in one client app, theoretically both native and template notification registration should succeed here. However, I only receive the APNS but no template.

Answer 1

Azure Messaging - RegisterTemplateAsync isn't working? This link solves my problem.
Note:
The problem was that this ExpiryTemplate wasn't clear for me. I did find any docs on that one, but apparently, it's a DateTime formatted
as en-us.
The expiry datetime MUST be formatted as en-us. Otherwsie, the RegisterTemplateAsync can't work.