By default Freebsd has root ssh disabled. Even in Ubuntu 14.04 it is not allowed with some other linux/unix distros as well.
Following error we get on screen even after entering correct password:
freebsd root ssh
To overcome this issue edit following ssh file: (ee is editor in freebsd)
ee /etc/ssh/sshd_config
in the file remove # from port 22
and remove # from
PermitRootLogin no
PermitRootLogin yes
then restart sshd demon
/etc/rc.d/sshd restart