ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2010);

service.Credentials = new WebCredentials("My user name","my pass");

System.Net.ServicePointManager.ServerCertificateValidationCallback =
        ((sender,certificate,chain,sslPolicyErrors) => true);

service.Url = new Uri("my web service url.WSDL");
    EmailMessage appointment = new EmailMessage(service);

appointment.Subject = "Test by me";
appointment.Body = "DateTime.Now";
appointment.ToRecipients.Add("xxxxxxx@gmail.com");

appointment.SendAnd

SaveCopy();