title: How to enable TLS 1.1/1.2 for Amazon Simple Email Service
body: <p>I have been successfully sending EMail using the Amazon-SES for years. However, for PCI compliance reasons, we have been attempting to disable TLS 1.0:</p>
  
  <pre><code>System.Net.ServicePointManager.SecurityProtocol = 
      SecurityProtocolType.Tls11 | 
      SecurityProtocolType.Tls12;
  </code></pre>
  
  <p>However, this causes exceptions when trying to send EMail:</p>
  
  <pre><code>AuthenticationException:
      A call to SSPI failed, see inner exception.
      The client and server cannot communicate, because they do not 
      possess a common algorithm
  </code></pre>
  
  <p>As soon as I add SecurityProtocolType.Tls back in, this again succeeds.
  Happens both with .NET 4.5 and 4.6.
  Using AWSSDK-SimpleEmail (v3.1.1.1) &amp; AWSSDK-Core Runtime (v3.1.2.1)</p>