ssh_exchange_identification: Connection closed by remote host

On the destination server, remove the known_hosts file:

rm ~/.ssh/known_hosts

Remove any relevant entries in your /etc/hosts.deny file:

/etc/hosts.deny:
# DenyHosts: Fri Jun 25 16:10:25 2010 | sshd: xxx.xxx.xxx.xxx
sshd: xxx.xxx.xxx.xxx

Also, try this in your /etc/hosts.allow file

/etc/hosts.allow:
SSHD: ALL