Skeddly's SAML workflow is modelled after the SAML workflow of AWS. AWS has created a guide to help troubleshoot SAML responses using debugging tools in your browser.
You can read their instructions here: How to View a SAML Response in Your Browser for Troubleshooting
There are also some useful browser plugins that allow you to view the SAML responses.
SAML Chrome Panel - I have used this, it works well