"HTTPS Error 404 - Not Found" error --- for RHEL all repos

On Foreman/Katello - Satellite is registered in RH (manifest imported), RHEL packages downloaded and visible trough Packages subpage, but not via https tho!;
On Client - it’s registered and subscribed (it has valid RH license) in Foreman/Katello, RHEL repos are visible and enabled trough: “yum repolist all” cmd, but whenever I’m trying to search/install, I am getting error: “HTTPS Error 404 - Not Found”;
There’s no such issue for CentOS repositories.

Expected outcome:
To be able to search and install RHEL packages

Foreman and Proxy versions:
Foreman 1.9

Foreman and Proxy plugin versions:
Katello 3.8

Other relevant data:
Exact same issue for deb packages for Ubuntu

Have you tried a basic subscription-manager refresh?