title: Server does not support secure connections
body: <p>I'm getting the error "Server does not support secure connections" with my code below.</p>
  
  <pre><code>SmtpClient client = new SmtpClient(exchangeServer);
  client.UseDefaultCredentials = false;
  client.EnableSsl = true;
  client.Credentials = new NetworkCredential(user, password);
  
  MailAddress from = new MailAddress(fromAddress);
  MailAddress to = new MailAddress(to);
  MailMessage mail = new MailMessage(from, to);
  
  // ...
  
  client.Send(mail);
  </code></pre>
  
  <p>How can I fix this issue?</p>