Setup .pkla rule for polkit

I'd like to start a systemd service using DBus in one of my apps which is run as non-root user myuser. For that I need to set up a PolicyKit where I'm using polkit 0.105 and added the following .pkla file to /etc/polkit-1/localauthority/50-local.d

[Test polkit]
Identity=unix-user:myuser
Action=org.freedesktop.systemd1.manage-unit-files;org.freedesktop.systemd1.manage-units
ResultActive=yes
ResultInactive=yes

Hoewever, that somehow didn't help it as I'm still getting the error Permission denied from DBus when it's runned as myuser where it works when started by root. As I understood polkit so far that's actually the way to set it up. What wonders me as well is that when executing pkaction it just returns nothing. Does polkit need some further setup? I just installed it via apt-get on an ubunutu 19.04 box.