GNOME "Unlock" icon greyed out when login as Windows Domain account

[panpanbebe]

I have issue with GNOME permission when trying to unlock the features on users setting page. I am using Windows domain admin account to login to CentOS, when I move my mouse to "unlock" icon, it said "System policy prevent changes, please contact your system administrator" I have local administrator privilege, but cannot operate this function, could anyone help me with this? Do I have to change Windows Active directory policy?