RHEL6 "Swtich User" in GUI environment does not work after Centrify Express Install

Hello,

I installed Centrify Express on two of my RHEL 6 systems. I joined the domain successfully and after I logon, I tried to "Switch User" via the GUI  but this does not work. 

I also tried this under the root login and still clicking on the "Switch User" button does not do anything.

Could you please advise what else needs to be modified for this to work properly?

Thank you.