c# - Error en la tarea Guardar cita para Windows Phone 8.1(el valor no se encuentra dentro del rango esperado)

windows-phone-8.1 appointment

Question

Debajo está el Código, yo solía guardar la tarea de cita para Windows Phone 8.1.

private async void Add-Click(object sender, RoutedEventArgs e)
{
// Create an Appointment that should be added the user''s appointments provider app.
var appointment = new Windows.ApplicationModel.Appointments.Appointment();
appointment.StartTime = timeconversion.AddMinutes(-10);
appointment.Location = sharingProgramTime; // appointment location
appointment.Subject = sharingProgramName; // appointment subject
appointment.Details = sharingProgramName + sharingProgramTime; // appointment details
appointment.IsAllDayEvent = false;
appointment.Reminder = new TimeSpan(0,10,0); // Ten minutes
appointment.BusyStatus = AppointmentBusyStatus.Busy;
// Get the selection rect of the button pressed to add this appointment
var rect = GetElementRect(sender as FrameworkElement);
// ShowAddAppointmentAsync returns an appointment id if the appointment given was added to the user''s calendar.
// This value should be stored in app data and roamed so that the appointment can be replaced or removed in the future.
// An empty string return value indicates that the user canceled the operation before the appointment was added.
String appointmentId = await Windows.ApplicationModel.Appointments.AppointmentManager.ShowAddAppointmentAsync(
appointment, rect, Windows.UI.Popups.Placement.Default);
}

Puedo guardar la cita en el calendario por primera vez. En la última ejecución del código siguiente,

String appointmentId = await Windows.ApplicationModel.Appointments.AppointmentManager.ShowAddAppointmentAsync(
appointment, rect, Windows.UI.Popups.Placement.Default);

La aplicación se cuelga debido al siguiente error, el valor no está dentro del rango esperado

Por favor, guíame para resolver el problema

Gracias