Office 365 Authentication... (Error: The connection's device credentials must be specified.)

Hi Everyone.

I have a problem. I am using the Simplified connection to connect to office 365.. http://msdn.microsoft.com/en-us/library/jj602970.aspx

However, I get an error "The connection's device credentials must be specified." when I run this LINQ Query.

 public string GetConfigValue(string key, IOrganizationService service)
        {
            var ocontext = new OrganizationServiceContext(service);

            var priorityMatrix = (from itil in ocontext.CreateQuery("apitil_itilsetting")
                                  where (string)itil["apitil_key"] == key&& itil["apitil_key"] != null&& itil["apitil_value"] != null&& ((OptionSetValue)itil["statuscode"]).Value == 1

                                  select new
                                  {
                                      priorityMx = itil["apitil_value"]
                                  }

                                 ).FirstOrDefault();

            return priorityMatrix != null ? priorityMatrix.priorityMx.ToString() : null;
        }

Do I really need the device ID and device password in my app.config file? I thought the authentication of the office365 does not need this?