Hi,
The principle documents for this can be found here:
https://helpx.adobe.com/enterprise/help/configure-sso.html
Principle things to look at are whether the correct certificate format has been uploaded to the dashboard, and whether the FirstName, LastName and Email attributes are passed by the Identity Provider.
You can use the SAML Tracer tool to get logs and help debug
https://addons.mozilla.org/en-US/firefox/addon/saml-tracer/
If the problem persists I would recommend opening a support ticket from your dashboard, go to the Support tab to do this.