title: how to send email without go to spam mail
body: <pre><code>        MailAddress mailFrom = new MailAddress("test@smtp.com");
          MailAddress mailTo = new MailAddress("tester@gmail.com");
          MailMessage mail2 = new MailMessage(mailFrom, mailTo);
          mail2.IsBodyHtml = true;
          SmtpClient client = new SmtpClient();
          client.Port = 25;
          client.Host = "xxx.xx.xx.xxx"; // smtp host ip
          mail2.Subject = "Testing.";
          mail2.Body = "Hello";
          mail2.SubjectEncoding = System.Text.Encoding.UTF8;
          mail2.BodyEncoding = System.Text.Encoding.UTF8;
          client.Send(mail2);
  </code></pre>
  
  <p>the above is my function that use to send an email via smtp, but I realized all the mail was located in my spam mail folder (Gmail). Is there anyway that can solve it ?</p>