string to = " xxxxxxx@qq.com";

            string from = " oa_service@yijiainternational.com";

            MailMessage message = new MailMessage(from, to);

            message.Subject = "Using the new SMTP client.";

            message.Body = @"Using this new feature, you can send an e-mail message from an application very easily.";

            SmtpClient client = new SmtpClient("smtp.zoho.com",465);

            client.Credentials = new System.Net.NetworkCredential(" oa_service@yijiainternational.com", "xxxxxxx");

            client.EnableSsl = true;

            client.DeliveryMethod = SmtpDeliveryMethod.Network;

           

            client.UseDefaultCredentials = true;

            try

            {

                client.Send(message);

            }

            catch (Exception ex)

            {

                Console.WriteLine("Exception caught in CreateTestMessage2(): {0}",

                            ex.ToString());

            }