How to register a system when SCA is enabled?

I have been shifted from Red Hat Customer portal to Hybrid cloud console. The problem is SCA may have been re-enabled and I can't find a way to disable it. As a result, an old problem came up: When I type in command subscription-manager list --installed, it shows "Not Subscribed", but when I try to register the system, it says the system is already registered. Please help me resolve this...