Lab13.1 error out for mariadb.service failed

I have followed the steps on 13.1 and setup config files up to step 7 is working fine. On step 8 I got following error:

[root@rdo-cc ~]# vim /etc/my.cnf.d/server.cnf

[root@rdo-cc ~]# getenforce

Permissive

[root@rdo-cc ~]# iptables -I INPUT -s storage1 -j ACCEPT

[root@rdo-cc ~]# systemctl stop mariadb

[root@rdo-cc ~]# galera_new_cluster

Job for mariadb.service failed because the control process exited with error co

de. See "systemctl status mariadb.service" and "journalctl -xe" for details.

[root@rdo-cc ~]#

Please advise. I am blocked.