CentOS 7 prohibits root account ssh login

[root@localhost ~]# cat /etc/redhat-release 

CentOS Linux release 7.4.1708 (Core) 

[root@localhost ~]# ssh -V
OpenSSH_6.6.1p1, OpenSSL 1.0.1e-fips 11 Feb 2013

vim /etc/ssh/sshd_config

Change PermitRootLogin yes to no

restart ssh 

systemctl restart sshd