Was getting error while trying to SSH to one of the server on port 22
ssh_exchange_identification: Connection closed by remote host
The issue is due to too many excessive connections on port 22
You can fix it by below change in SSH config
MaxStartups variable in /etc/ssh/sshd_config to ,
port 2222 or any port you need to and
MaxStartups 100
Restart the SSH service ,
service sshd restart