RHCS 4 - ansible playbook fails on "TASK [ceph-validate : fail when dashboard_admin_password and/or grafana_admin_password are not set]"

Issue

Ansible playbook run fails of following task with error " msg: you must set dashboard_admin_password and grafana_admin_password."

        "TASK [ceph-validate : fail when dashboard_admin_password and/or grafana_admin_password are not set] ***",
        "Wednesday 10 June 2020  14:06:16 +0200 (0:00:00.518)       0:01:33.203 ******** ",
        "fatal: [osds-0]: FAILED! => changed=false ",
        "  msg: you must set dashboard_admin_password and grafana_admin_password.",
        "fatal: [osds-1]: FAILED! => changed=false ",
        "fatal: [osds-2]: FAILED! => changed=false ",