My bad!
It was
adinfo -A -u username
Sorry.
Do me a favor, as root, switch user (su) to an ad user (you'll be able to do it), then try to su to another known user (type the correct password). If you are able to su from the normal account to the other user with the password, then your issue is with OpenSSH or the GUI.
I have to continue working on something else now. Ciao.
R.P