Why does 'ssh' and 'scp' work to one and not another?

[joe at actionline.com]

> Failed password for joe from 192.168.0.68
> seems pretty clear to me

We have known all along that there is a failed password,
but I don't know how to fix that. Both the user and root
passwords work to log in to this computer, but the same
passwords do not work to log in remotely.

I have tried changing the passwords, but the system will
not allow me to do so.