Candlepin Failure when updating Red Hat Satellite 6.2 to RHEL 7.4

Issue

• When updating the base of Red Hat Satellite 6.2 to Red Hat Enterprise Linux 7.4, you receive candlepin service failures or satellite upgrade failures.

[root@satellite6 ~]# hammer ping
candlepin:
    Status:          FAIL
    Server Response:
candlepin_auth:
    Status:          FAIL
    Server Response:
pulp:
    Status:          ok
    Server Response: Duration: 34ms
foreman_tasks:
    Status:          ok
    Server Response: Duration: 21ms

[root@satellite6 ~]# cat  /etc/redhat-release
Red Hat Enterprise Linux Server release 7.4 (Maipo)