I would use this command on the
new server to create your key pairs. Not sure why "protocol 1" is even coming up in the screenshot you posted:
On the
new server:
su root
ssh-keygen -b 2048 -t rsa -f /root/.ssh/mynewkey
<hit return and use NO passphrase>
Manually copy the contents of
/root/.ssh/id_rsa.pub on the
NEW server to the
/root/.ssh/authorized_keys file on the
OLD server.
If your old server is also a GCE, you may need to enter the "root" usernames and keys here:
Google Cloud Platform
On both machines, make sure the
/root/.ssh/ folder has chown root:root permissions and chmod 700
On both machines, make sure the
contents of
/root/.ssh/* folder has chown root:root permissions and chmod 600
On both machines, do:
service sshd restart
From the command line of the new server, you should be able to log directly in to the old server using this command:
ssh -24kv -l root 35.227.27.42 -p 22
If you can't log in directly like this, Plesk will not be able to either.