Make sure to :

• Register to notification in AppDelegate:

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) { completionHandler([.alert, .sound, .badge])}

• in didFinishLaunchingWithOptions :

     func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
   UNUserNotificationCenter.current().delegate = self
   return true}