Configure Idp-Initiated SAML SSO using the sample Node.js app

I made use of the sample Node.js app to implement SAML based SSO with my ADFS server. I follow the steps at

Everything works great! Then, I tried configuring for Idp-Initiatied SSO. But, failed. It said “There could be a misconfiguration in the system or a service outage…” From the dashboard, I can see the SAML Success Login event.

IdP-Initiated SSO setting of the SAML connection look like this:
1, Default Application: Default App
2. Response Protocol: SAML
3. Query String: empty

Did I miss anything?