Failed to get D-Bus connection

After setting up the systemd service for Caddy, I received the following error when trying to start the service:

$ sudo systemctl start caddy.service
Job for caddy.service failed. See 'systemctl status caddy.service' and 'journalctl -xn' for details.
$ systemctl status caddy.service
Failed to get D-Bus connection: No such file or directory

The fix was pretty easy. It turns out that dbus was not installed on the system. I installed it and then the service worked perfectly:

$ apt-get install -y dbus

For what it’s worth, I did this on a Google Cloud Compute Engine instance that I initialized with the default Debian install.