CentOS

We have Linux server and cannot login via ssh because its service is stopped. when we are trying to start it give us the following error.

Error: /etc/ssh/sshd_config line 23: directive 'protocol' is not allowed within a match block



please help us recover this problem and start the ssh service.

Thanks..

It sort of tells you what's wrong in the error. In /etc/ssh/sshd_config you have a "Match " directive and under that, you've attempted to add a "Protocol" line and it's not allowed there. You've either put your Match directive in the wrong place in the file or you've added Protocol under it where it's not allowed.