Failed to issue method call: Unit ... failed to load: No such file or directory

I have a systemd definition file installed, but systemd fails to use it. What might the trouble be, or how can I debug it?

ettin:~# ls -l /etc/systemd/system/efl_test_daemon.service 
-rwxr-xr-x 1 root root 145 Aug 18 13:11 /etc/systemd/system/efl_test_daemon.service
ettin:~# /bin/systemctl start efl_test_daemon.service
Failed to issue method call: Unit efl_test_daemon.service failed to load: No such file or directory.

Just like Michael Hampton said in the question comment, you created a new service file and you need to run this:

systemctl daemon-reload

I'm posting the answer for easy access. If Michael posts his answer I will be happy to remove mine.