private async Task <OAuthToken> Send(HttpPropertyList parameters) { OAuthToken token = null; try { string body = parameters.FormEncode(); string request = await new HttpHelper(_settings.EndPoint) .SendRequest(HttpMethod.Post, "/oauth/access_token", body, null, "application/x-www-form-urlencoded"); token = OAuthToken.ParseJson(request); } catch (InvalidResponseException ex) { if (ex.InvalidResponseEntity.BadRequest == "invalid_client") { OnAuthorizationFailed(); } throw; } return(token); }