If you’d found this page you might already have trouble with this software. Afaik the major issue is, that policykit by itself does not log what it prohibits. For this you need a special policy rule file under /etc/polkit-1/rules.d/, which get written in javascript for some poor reason:

The number 99 is believed to be the last rule file in that directory, so that when it gets called it will log to syslog. Check journalctl -xef while running the command that previously failed to get an understanding what wents wrong. Note, that policykit is smart enough to recognize rule changes by itself so that changing or adding files to that directory is enough. Just in case systemctl restart polkit restarts polkit.

Fix permission problems by example

Fix ‘mount failed’ issues caused by udisk (make sure you are in the ‘storage’ group):

Fix NetworkManager not being able to connect ‘permission denied’-issue (make sure you are in the ‘network’-group):

Fix permission issue with pcsc-tools (used for hbci online banking):

Fix permissions so that tools like virt-manager with libvirt work:

Fix permissions for pamac update tray icon and installation manager (user must be member of the wheel group):