SAML Connection Timed Out

I’ve configured my Open edX instance as a Service Provider and linked it to a platform called Channeltivity as Identity Provider. Everything looks fine and the logs in Channeltivity are ok but when I try to log in I´m getting “The connection has timed out” on the Open edX side. So it seems like something isn´t responding.

Has anyone had this issue? Or do you know what might be causing it?
I don´t know how to troubleshoot this