Linux machine (Fedora) restarted immediately after suspend

My Dell Laptop restarted immediately after suspend when using Fedora 28  (Linux). To debug this, I used the following commands :

  1. systemd-inhibit –list        – This shows the programs that can inhibit suspending the system.
  2. systemctl suspend                – Request a suspend. Similar to closing the laptop lid.
  3. systemctl suspend -i           – Override inhibit and suspend, preventing programs that are inhibiting suspend from being able to inhibit.

I found that I could kill off processes listed by (1) and see which one was causing problems. In my case the xfce4-power-manager was the culprett