Duplicate posted in case it helps someone in the future:
For CWP->CWP Migration, you have to stand on your head, pat your belly, and rub your feet at the same time in order to make this work. Actually, I just had the opportunity to do a CWP -> CWP migration, so here was my solution to the failed connection errors:
Disable the firewall (CSF & LDF) on both servers.
On both servers, reset the r00t password to be 8 characters or fewer.
In /etc/ssh/sshd_config
set:
PermitRootLogin yes
StrictModes no
Restart sshd:
service sshd restart
On the source server, set up the API key (CWP Settings > API Manager) for CWP Migration using the default CWP template.
On the receiving server, use the interface in User Accounts > CWP->CWP Migration.
After successfully migrating the accounts, revert all changes to your SSH configuration, restart the ssh daemon, reset the r00t passphrases to strong ones, and re-enable the firewalls.