Query on SingleSignOn

Hi All,

We are trying to integrate single sign on concept and we got struck with the below error.
"The SuiteSignOn object customsso_xpress is not configured for use with this script. You must specify the script as a connection point for this SuiteSignOn" .

The steps which we were performed to integrate SSO are
1. Created Suitesiteon page and provided the connection point information.
2. Created Portlet script. Please see the below script
// create a portlet object
function buildPortlet(portlet, column)
{
title = 'My Custom SSO Portlet!';
portlet.setTitle(title)
var url = nlapiOutboundSSO('customsso_xpress');
var content = '<iframe src="'+url+'" align="center" style="width: 100%; height: 600px;   margin:0; border:0; padding:0"></iframe>';