systemd invalid argument - debugging delayed hibernation service file

Question

I'm trying to implement the delayed hibernation unit. I'm on arch/antergos.

>>> systemctl enable suspend-to-hibernate.service
Failed to enable unit ...to-hibernate.service: Invalid argument

systemd-analyze verify ...hibernate.service responds with an empty output.

I copied the unit file straight from the arch wiki and changed SLEEPLENGTH to 1 hour. How can I debug the issue? How can I make systemd issue more descriptive error messages?

suspend-to-hibernate.service

[Unit]
Description=Delayed hibernation trigger
Documentation=https://bbs.archlinux.org/viewtopic.php?pid=1420279#p1420279
Documentation=https://wiki.archlinux.org/index.php/Power_management
Conflicts=hibernate.target hybrid-sleep.target
Before=sleep.target
StopWhenUnneeded=true

[Service]
Type=oneshot
RemainAfterExit=yes
Environment="WAKEALARM=/sys/class/rtc/rtc0/wakealarm"
Environment="SLEEPLENGTH=+1hour"
ExecStart=-/usr/bin/sh -c 'echo -n "alarm set for "; date +%%s -d$SLEEPLENGTH | tee $WAKEALARM'
ExecStop=-/usr/bin/sh -c '\
  alarm=$(cat $WAKEALARM); \
  now=$(date +%%s); \
  if [ -z "$alarm" ] || [ "$now" -ge "$alarm" ]; then \
     echo "hibernate triggered"; \
     systemctl hibernate; \
  else \
     echo "normal wakeup"; \
  fi; \
  echo 0 > $WAKEALARM; \
'

[Install]
WantedBy=sleep.target

Answer 1

As given in the Arch wiki page, the file should be in /etc/systemd/system/. There are several directories where systemd looks for unit files, and /etc/systemd/system/ is where a system administrator should place their service files. See man systemd.unit.

After creating or a modifying a file in these directories, you have to run systemctl daemon-reload, which gets systemd to recheck its directories for new or modified units. Only then can you enable or start a new service.