lightdm authentication failure for one user

[François Patte]

Bonjour,

I have problem with lightdm greeter: one user cannnot log-in: I have
this message in /var/log/lightdm/lightdm.log:

Authenticate result for user cath  : User not known to the underlying
authentication module

What does it mean and how to recover?

selinux is disabled.

Thank you.


-- 
François Patte
UFR de mathématiques et informatique
Laboratoire CNRS MAP5, UMR 8145
Université Paris Descartes
45, rue des Saints Pères
F-75270 Paris Cedex 06
Tél. [phone]
http://www.math-info.univ-paris5.fr/~patte