Hi, similiar issue is happening to me.
I am unable to find some training materials, but other materials I do.
There are some training materials that are not displayed when looking for them into the learning Catalog.
But if I try using direct URL, they show me the message "We are sorry, this content is not available", for example looking for following URLs https://rol.redhat.com/rol/app/courses/do280-4.5/pages/pr01 related to training "Red Hat System Administration I (DO280)"
https://rol.redhat.com/rol/app/courses/rhcsa650e-8.2/pages/pr01 related to training "Red Hat Certified System Administrator (RHCSA) (DO200)"
I know those are valid URL because other teammates can reach them and content is shown to them.