For some reason lately when I try to set the date using the interface, or simply install a .rpm by double clicking the dialog that should prompt me to input my passowrd just shakes like it has a bug. The dialog window that shakes has the titleAuthenticatePrivileges are required to change the system time/install software/etcAnn application is attempting to perform an action that requires privileges. Authentication as the super user is required to perform this actionAuthenticat FailureAnd I have to options: Cancel and Authenticate. The problem is this windows just shakes and disappears so I can't actually press the Authenticate button.And after this window disappears I get a new one that says:Failed to set the system time:Not Authorized for action org.gnome.clockapplet.mechanism.settimeWhy is this happening? A few days ago I was able to input my password and install software now this happens. 
CentOS GUI problem using Gnome
centos;gnome;gui;interface