I have a server with SLES 11.
Yast worked so far well. It is still working, as I can open the YaST control center.
Just when I pick on the left pane of the yast menu:
Security and Users
and then in the right pane
User and Group Management
very shortly the Window
YaST2 - users @ servername
opens. It runs through all the points and makes its x in front:
x   Read the default login settings
x   Read the default system settings
x   Read the configuration type
x   Read the user custom settings
x   Read users and groups
=> Build the cache structures
Then underneath:
Building the cache structures
... 100%
But then rather than that the User and Group module in Yast opens, I am returned to the
YaST2 Control Center (where I started out).

What is happening here? Everything else in yast works.
Do I need to reinstall YaST? Which packages?
Can I somehow create a log file when I try to open user and group management?
But yast does not bring an error message, but just refuses to open user and group management.
I am logged in as root.
Does yast need a server certificate for Users and Group management?
Would anyone have an idea?

Thank you.