SSH: failed password after fresh install

[Bryn Dyment]

I've installed two FreeBSD boxes on my LAN.  On the first box, the only
thing I did after the install process was edit "/etc/ssh/sshd_config",
setting "PermitRootLogin" to "yes", then issuing "killall -1 sshd".  After
this change, I could successfully connect to this box via my SSH client.

I did the same thing with the second box, but I cannot login via my SSH
client.  I get an invalid password error, and "Failed password" also appears
on the server in "/var/log/auth.log".  I have rebooted, and also
reinstalled, to no avail.  Any idea as to what could be causing this error?