[arch-general] Desktop Notifications

kalu is used on my machine to manage AUR upgrades notifications. This package has been working well until now. Notification pop-up doesn't work. In the mate desktop, when going to system > preferences > Notification pop-up, clicking preview leaves me with this error: ---------------- Error while displaying notification: Error calling StartServiceByName for org.freedesktop.Notifications: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ChildExited: Process org.freedesktop.Notifications exited with status 127 ----------------------- I have no idea how to solve it. Note: $ notify-send "test" doesn't show anything Thank you for suggestions.