I agree with @aflato.
Your NotificationCommand Object is defined in
<icinga2dir>/conf.d/commands.conf by default. If you want to include the hole directory recursively, you have to include it at
But note that under
conf.d there are some basic and example configurations which you should check again if necessary.
Otherwise you can import selected files. For example:
I hope I could help you.
Greetings from Germany