Unable to run reboot, shut down or others without sudo in terminal.

I am currently running dietpi on my raspberry pi 3 b+ and I’m not sure as to the cause of this issue, but I’ve not found any solution in any of my reading and searching. The issue I’m having is that anything that requires elevated permissions is simply failing to launch. For instance, when I run sudo dietpi-launcher from a terminal, it launches without any issues. However, if I click on the link in my settings menu, the terminal window will open, then immediately close. If it were just those sorts of things, I’d easily deal with it. But where it becomes a problem is when I click restart, or shutdown. It logs out and takes me back to the lightdm login screen, with the power options on that screen being entirey unavailabe. With this, the only way I can shutdown is by switching to another terminal and running sudo halt. It seems to me there must be something in the permissions that is keeping it from running these. Any help anyone could offer to help would be extremely appreciated, and I’ll gladly do any research that is needed. I’m not the most savvy user when it comes to linux, but I’m not afraid of a terminal, and I know enough to get around a little bit. If anyone needs to know, I’m currently running the xfce desktop, but it also gave me the same issues on both lxde and MATE.

Verified: https://github.com/MichaIng/DietPi/issues/2857

Only occurs when logging in as non-root. PolicyKit fails with GDBus error, although dbus is up. We will investigate.

Issue has been resolved for DietPi v6.25: https://github.com/MichaIng/DietPi/pull/2917

To apply the fix now:

sed -i 's|/usr/sbin/lightdm|systemctl start lightdm|' /DietPi/dietpi/dietpi-login