Where to define the ansible user to allow fetching the inventory from foreman

I can’t configure the ansible correctly to allow ansible to fetch the inventory from foreman.
I don’t know where the user in the yml file comes from.
I tried adding a user ‘ansible_inventory’ with the role ‘remote execution user’ but I get error 111. Connection refused when running ansible-inventory --graph on the foreman-server
Expected outcome:
The inventory is acquired from foreman - the documentation goes more into detail how to configure this (or is easier to find :wink: )
Foreman and Proxy versions:
Foreman: (not showing, installed only a few weeks ago, from centos repos => there seems to be a problem connecting to port 8443 ass well)
Foreman and Proxy plugin versions:
foreman_remote_execution: 1.6.7
foreman_ansible: 2.2.14
Other relevant data:
[e.g. logs from Foreman and/or the Proxy, modified templates, commands issued, etc]
(for logs, surround with three back-ticks to get proper formatting, e.g.)

[root@foreman ~]# ansible-inventory --graph
 [WARNING]:  * Failed to parse /etc/ansible/inventory.foreman.yml with foreman plugin:
('Connection aborted.', error(111, 'Connection refused'))

 [WARNING]: Unable to parse /etc/ansible/inventory.foreman.yml as an inventory source

 [WARNING]: No inventory was parsed, only implicit localhost is available