Centos7 permission to open ssh root account

Description of the problem, in between doing each machine free confidential login time, there is one server others can not ssh in the past, but it can find other ssh server, followed by the root account does not have permission to open ssh, so the next record, how to root accounts opened ssh permissions

First, verify that the firewall is not the problem, then the problem is not confirmed after the firewall to see whether the rights corresponding root has a corresponding.

vim /etc/ssh/sshd_config

Under edit this file

The corresponding login no comment out, open yes, and then restart the ssh service, then to OK!