Comment # 6 on bug 1204114 from Jonathan Kang

Try adding the following to /etc/polkit-1/rules.d/00-log-access.rules, restart
the system, reproduce this issue and check "sudo journalctl -b" for
00-log-access.rules related logs.

> polkit.addRule(function(action, subject) {
>     if (action.id == "org.freedesktop.NetworkManager.settings.modify.system") {
>         polkit.log("action=" + action);
>         polkit.log("subject=" + subject);
>     }
> });