C发送邮件465端口也是失败的！阿里的人来说一下

MailMessage mail = new MailMessage();
            mail.From = new MailAddress("xsz_help@sina.com");
            mail.To.Add(new MailAddress(emailAddress));
            mail.Subject = subject;
            mail.IsBodyHtml = true;
            mail.Body = "<h1>密码重置为"+newPasswords+"</h1>";
            //try
            //{
                SmtpClient smtp = new SmtpClient();
                //smtp.Host = "smtp.sina.com";
            //smtp.Host = "smtp.qq.com";
            smtp.Host = "smtp.163.com";
            smtp.UseDefaultCredentials = true;
                smtp.EnableSsl = true;
                //smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
                smtp.Port = 465;
                //nbxchxceju
               // smtp.Credentials = new NetworkCredential("xsz_helper@qq.com", "-----");
            //smtp.Credentials = new NetworkCredential("xsz_help@sina.com", "---");
            smtp.Credentials = new NetworkCredential("xsz_help@163.com", "-------");
            smtp.Send(mail);