sudo systemctl status lightdm
 lightdm.service - Light Display Manager
   Loaded: loaded (/lib/systemd/system/lightdm.service; enabled)
   Active: failed (Result: start-limit) since Thu 2017-03-30 11:05:44 UTC; 39s ago
     Docs: man:lightdm(1)
  Process: 854 ExecStart=/usr/sbin/lightdm (code=exited, status=1/FAILURE)
  Process: 849 ExecStartPre=/bin/sh -c [ "$(cat /etc/X11/default-display-manager 2>/dev/null)" = "/usr/sbin/lightdm" ] (code=exited, status=0/SUCCESS)
 Main PID: 854 (code=exited, status=1/FAILURE)

Mar 30 11:05:44 raspberrypi systemd[1]: Failed to start Light Display Manager.
Mar 30 11:05:44 raspberrypi systemd[1]: Unit lightdm.service entered failed state.
Mar 30 11:05:44 raspberrypi systemd[1]: lightdm.service holdoff time over, scheduling restart.
Mar 30 11:05:44 raspberrypi systemd[1]: Stopping Light Display Manager...
Mar 30 11:05:44 raspberrypi systemd[1]: Starting Light Display Manager...
Mar 30 11:05:44 raspberrypi systemd[1]: lightdm.service start request repeated too quickly, refusing to start.
Mar 30 11:05:44 raspberrypi systemd[1]: Failed to start Light Display Manager.
Mar 30 11:05:44 raspberrypi systemd[1]: Unit lightdm.service entered failed state.