Cannot subscribe Satellite 6 host with RHSM

Issue

• I'm trying to install Satellite 6 on a RHEL 6 server and when I try to attach the Satellite 6 subscription to it, with subscription-manager, I cannot see available subscription for it

[root@satellite ~]# subscription-manager register --auto-attach

The system has been registered with ID: d875dde9-0f55-4aeb-b72f-37c7c91cbd52
Installed Product Status:

Product Name: Red Hat Software Collections (for RHEL Server)
Status:            Not subscribed

Product Name: Red Hat Enterprise Linux Server
Status:            Subscribed

Product Name: Red Hat Satellite
Status:            Not subscribed

No available subscriptions found for installed products

• I've checked the output of subscription-manager list --available --all but cannot see Satellite 6 subscription