The error is because the polkit authentication agent helper is not running.

The GUI window which asks for password

We can use any polkit helper like polkit-gnome or any other [–more–]

To fix this error execute below command on another terminal, or add it to your window manager script or at startup⌗ 

/usr/lib/polkit-gnome/polkit-gnome-authentication-agent-1

This will fix the issue.⌗