make sure you are correctly configured:
subscription-manager list --consumed
you may need to add a subscription:
subscription-manager register --auto-attach --force
if everything is OK:
subscription-manager repos --enable rhel-7-server-extras-rpms
subscription-manager repos --enable rhel-7-server-optional-rpms
subscription-manager repos --enable rhel-7-server-rpms
subscription-manager repos --enable rhel-ha-for-rhel-7-server-rpms
