on new server copy Public Key from: # cat /root/.ssh/id_rsa.pub
and paste Public key to Old server: # nano /root/.ssh/authorized_keys
And to be clear, this had no bearing on my connection difficulties. I already had my SSH key pair in place and it was in the authorized_keys, so that was not the issue. I too experienced the "Connection not reached - the following error occurred" error message before running down my solution list.
(For sure, it was the standing on the head part that solved it...)