title: AggregateException "One or more errors occurred.An error occurred while sending the request."
body: <p>I tried to post a file to an API rest from my WCF .Net framework 4.5. Here is my code:</p>
  
  <pre><code>public string CreateConclusion(string[] instanceUIDs)
      {
          var root = @"C:\";
          string filename = "1.2.840.114257.1.9.1245.56421.52314.1119854.01248.dcm";
  
              using (var client = new HttpClient())
              {
                  var stream = new FileStream(root + filename, FileMode.Open);
  
                  using (var content =
                      new MultipartFormDataContent("Upload----" + DateTime.Now.ToString(CultureInfo.InvariantCulture)))
                  {
                      content.Add(new StreamContent(stream), "fileToUpload", filename);
  
                      using (var message = client.PostAsync("https://localhost:44343/api/ConclusionReports/UploadFile", content).Result)
                      {
                          var input = message.Content.ReadAsStringAsync();
  
                          return !string.IsNullOrWhiteSpace(input.Result) ? Regex.Match(input.Result, @"http://\w*\.directupload\.net/images/\d*/\w*\.[a-z]{3}").Value : null;
                      }
                  }
              }
  
      }
  </code></pre>
  
  <p>It doesn't work and throw an exception: "One or more errors occurred.An error occurred while sending the request."</p>
  
  <p>Does anyone can help me to solve this problem? Thank you in advance</p>