public async Task <IActionResult> OnPostAsync(int?id)
        {
            Appointment = await _context.Appointment
                          .Include(a => a.Client).FirstOrDefaultAsync(m => m.Id == id);

            EmailHandler smtp = new EmailHandler();

            //Sends email with Appointment message
            await smtp.SendMailAsync(smtp.CreateAppointmentEmail(Appointment));

            return(Page());
        }