WAK - WebAPIKit - on-complete error when retrieving JSON

 {ERR} [184044FE]'on-complete' User Action invocation failed hard with error: Exception has been thrown by the target of an invocation.
 UnityEngine.Debug:LogError(Object)
 hg.ApiWebKit.Configuration:Log(String, LogSeverity) (at Assets/WAK.core/WAK/CORE/Configuration.cs:175)
 hg.ApiWebKit.Configuration:LogInternal(String, String, LogSeverity) (at Assets/WAK.core/WAK/CORE/Configuration.cs:198)
 hg.ApiWebKit.core.http.HttpOperation:Log(String, LogSeverity) (at Assets/WAK.core/WAK/CORE/core/http/HttpOperation.cs:29)
 hg.ApiWebKit.core.http.HttpOperation:tryUserAction(String, Object[]) (at Assets/WAK.core/WAK/CORE/core/http/HttpOperation.cs:242)
 hg.ApiWebKit.core.http.HttpOperation:<SendRequest>m__4(HttpResponse) (at Assets/WAK.core/WAK/CORE/core/http/HttpOperation.cs:213)
 hg.ApiWebKit.core.http.HttpAbstractProvider:BehaviorComplete() (at Assets/WAK.core/WAK/CORE/core/http/HttpAbstractProvider.cs:128)
 hg.ApiWebKit.providers.<sendImplementation>c__IteratorB:MoveNext() (at Assets/WAK.core/WAK/providers/HttpWWWClient.cs:59)

 namespace hg.ApiWebKit.cyclingsim.client
 {
     public class PlayerManager : MonoBehaviour
     {
 
         public GameObject CurrenciesGameObj; //this is the gameObject that holds the currencies text components inside
         public GameObject UserProfileGameObj; //this is the gameObject that holds the user profile info like Level and Energy text components inside
 
         public Slider NRJSlider;
 
         public Text TextPlayerLevel;
         public Text TextEnergyTimer;
         public Text TextXPToNextLevel;
 
         public Text TextTrainingPoints;
         public Text TextGems;
         public Text TextCash;
 
         public IEnumerator SqlLoad(string playerid)
         {
             yield return new WaitForSeconds(2.0f);
 
             new hg.ApiWebKit.cyclingsim.operations.LoadPlayer()
             {
                 playerid = playerid
             }.Send(null, null, onComplete);
 
             yield break;
         }
 
         private void onComplete(LoadPlayer operation, hg.ApiWebKit.core.http.HttpResponse response)
         {
             // Update currencies
             TextCash.text = operation.response.Cash.ToString();
            ...
          }

 namespace hg.ApiWebKit.cyclingsim.operations
 {
     [HttpGET]
     [HttpPath("mytestproj", "/v1/players/{$playerid}")]
     [HttpProvider(typeof(hg.ApiWebKit.providers.HttpWWWClient))]
     [HttpAccept("application/json")]
     [HttpContentType("application/x-www-form-urlencoded; charset=UTF-8")]
     [HttpRequestHeader(
         VariableName = "myAuthHeaderName",
         VariableValue = "myAuthHeaderValue")]//,
     //Converter= typeof(hg.ApiWebKit.converters.BasicAuthEncode))]
     public class LoadPlayer : HttpOperation
     {
         [HttpUriSegment("playerid")]
         public string playerid;
 
         [HttpResponseJsonBody] // expected JSON object response
         public models.Player response;
     }
 }