title: .NET Core Refit HTTPS errors
body: <p>I have the below code, which uses Refit to make an HTTPS call. It works from a console application targeting the .NET framework 4.6.1.</p>
  <p>When I run the exact same code from a console application targeting .NET Core 2.1 I get an error:</p>
  <blockquote>
  <p>The SSL connection could not be established... An unknown error occurred while processing the certificate</p>
  </blockquote>
  <p>I'm using Refit version 4.5.6</p>
  <pre><code>System.Net.ServicePointManager.SecurityProtocol =
      SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;
  
  var baseAddress = new Uri(BaseHttpsAddress);
  var httpClientHandler = new HttpClientHandler
  {
      ClientCertificateOptions = ClientCertificateOption.Automatic
  };
  
  var httpClient = new HttpClient(httpClientHandler) { BaseAddress = baseAddress, Timeout = _requestTimeout };
  
  var service = RestService.For&lt;IMyService&gt;(httpClient);
  
  var result = await service.GetUsers();
  </code></pre>
  <p>In fact when targeting .NET Core 2.1 all my HTTPS calls fail, but my HTTP calls work fine.</p>
  <p>Is there some configuration or something to get HTTPS calls working in a .NET Core 2.1 application using Refit?</p>