title: System.Net.WebException when using WebClient: Can not create SSL/TLS secure channel
body: <p>When I execute the following code</p>
  
  <pre><code>System.Net.ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, errors) =&gt; {
      return true;
  };
  var webClient = new WebClient();
  var s = webClient.DownloadString("https://jtlplugins.x-volution.de/api.php?apikey=yS5VS7OiG1ukiIqLzCSYuFCjeF1qSskKOQeCtVxh&amp;do=pruefe_app&amp;cappid=123&amp;chardwareid=DC0D-BFEA-6F79-58DE-21E9-BA3A-B288-C46F&amp;clizenzschluessel=123");
  </code></pre>
  
  <p>I always get a System.Net.WebException: Can not create SSL/TLS secure channel</p>
  
  <p>When I execute this</p>
  
  <pre><code>https://jtlplugins.x-volution.de/api.php?apikey=yS5VS7OiG1ukiIqLzCSYuFCjeF1qSskKOQeCtVxh&amp;do=pruefe_app&amp;cappid=123&amp;chardwareid=DC0D-BFEA-6F79-58DE-21E9-BA3A-B288-C46F&amp;clizenzschluessel=123
  </code></pre>
  
  <p>for example direct in Firefox or Internet Explorer, it works and give back a result.</p>
  
  <p>What should I do that this is also executed with my code like in the browser?</p>
  
  <p>I have read the other posts in stackoverflow about this problem - but they are not solving my problem :-(</p>