I've seen that error when the permissions (on ONE of the nodes) on /home/asterisk/.ssh are incorrect -- Normally, too lax.
I'm pretty sure running this on both machines will fix it:chmod 755 /home/asterisk/.ssh
chmod 744 /home/asterisk/.ssh/*
chmod 700 /home/asterisk/.ssh/id_rsa
If it doesn't, feel free to reply here, or, open a commercial support ticket.
--Rob