title: I'm getting a MailKit.Security.SslHandshakeException when trying to connect to "smtp.office365.com"
body: <p>I am trying to use MailKit to send an email message via "smtp.office365.com".  Here is the code I'm using.</p>
  
  <pre class="lang-cs prettyprint-override"><code>using (var client = new SmtpClient(new ProtocolLogger("smtp.log")))
  {
      client.ServerCertificateValidationCallback = (s, c, h, e) =&gt; true;
      client.Connect("smtp.office365.com", 587, SecureSocketOptions.SslOnConnect);
      client.Authenticate(new SaslMechanismNtlmIntegrated());
      Debug.WriteLine(client.IsAuthenticated);
      client.Send(message);
      client.Disconnect(true);
  }
  </code></pre>
  
  <p>The <code>SaslMechanismNtlmIntegrated</code> class I got from <a href="https://github.com/jstedfast/MailKit/issues/332#issuecomment-398300208" rel="noreferrer">this comment</a> on GitHub.</p>
  
  <p>Whenever I run this code, I get an <code>SslHandshakeException</code>.</p>
  
  <p>Here are the details of the exception:</p>
  
  <pre><code>MailKit.Security.SslHandshakeException
    HResult=0x80131500
    Message=An error occurred while attempting to establish an SSL or TLS connection.
  
  One possibility is that you are trying to connect to a port which does not support SSL/TLS.
  
  The other possibility is that the SSL certificate presented by the server is not trusted by the system for one or more of the following reasons:
  1. The server is using a self-signed certificate which cannot be verified.
  2. The local system is missing a Root or Intermediate certificate needed to verify the server's certificate.
  3. The certificate presented by the server is expired or invalid.
  
  See https://github.com/jstedfast/MailKit/blob/master/FAQ.md#InvalidSslCertificate for possible solutions.
    Source=MailKit
    StackTrace:
     at MailKit.Net.Smtp.SmtpClient.&lt;ConnectAsync&gt;d__70.MoveNext()
     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at MailKit.Net.Smtp.SmtpClient.Connect(String host, Int32 port, SecureSocketOptions options, CancellationToken cancellationToken)
     at QuoteAndOrder.SpecialsQuoteWindow.BtnEmail_Click(Object sender, RoutedEventArgs e) in SpecialsQuoteWindow.xaml.cs:line 501
  
  Inner Exception 1:
  IOException: The handshake failed due to an unexpected packet format.
  </code></pre>
  
  <p>I went to the <a href="https://github.com/jstedfast/MailKit/blob/master/FAQ.md#InvalidSslCertificate" rel="noreferrer">FAQ</a> mentioned in the details, but the workaround given did not resolve the issue.</p>