title: Unknown authentication scheme when liking post (LinkedIn API)
body: <p>Below goal is to like a post!</p>
  
  <p>I get an error when trying to "Like" a post with the REST API (LinkedIn)
  I have created an accesstoken with all scopes:</p>
  
  <p><strong>scope=w_messages+rw_company_admin+rw_nus+r_emailaddress+r_basicprofile+rw_groups+r_fullprofile+r_network+r_contactinfo</strong></p>
  
  <p>I can retreive comments from posts with the accesstoken which tell us that I have set it up correctly as a base.</p>
  
  <p>However when I try to like a comment with the below code (just after in the same code where I have collected a comment), I receive this error:</p>
  
  <p><strong>"unknown authentication scheme"</strong></p>
  
  <p>I wonder why I can't like a post when I have set all scopes and I also have them checked in my application settings. Also notice that the postID is correct as I can retreive the comments for the post?</p>
  
  <p>Thank you!</p>
  
  <pre><code>                        String accessToken = "MYLONGTOKEN"; //Just dummy example
                          String postID = "g-123456-S-123456789"; //Just dummy example
                          String requestUrl = "https://api.linkedin.com/v1/posts/" + postID  + "/relation-to-viewer/is-liked&amp;oauth2_access_token=" + accessToken;
  
                          RestSharp.RestClient rc = new RestSharp.RestClient();
                          RestSharp.RestRequest request = new RestSharp.RestRequest(requestUrl, RestSharp.Method.PUT);
                          request.AddHeader("Content-Type", "application/json");
                          request.AddHeader("x-li-format", "json");
  
                          request.RequestFormat = RestSharp.DataFormat.Json;
  
                          restResponse = (RestSharp.RestResponse)rc.Execute(request);
                          responseStatus = restResponse.ResponseStatus;
  
  
                          //unknown authentication scheme
                          MessageBox.Show(restResponse.Content.ToString());
  </code></pre>