RedHat 8

I login as root.
Issue "startx".
In the GUI, I click  the RedHat > System Settings > Users and Groups
Nothing happens.  The system returns to the desk top.

Then I login as ggambill.
Issue "startx".
In the GUI, I click  the RedHat > System Settings > Users and Groups
The system asks for the su password which I provide.
Nothing happens.  The system returns to the desk top.

Any ideas how to repair this