Hi @frahmn Welcome to the community
I think perhaps you're confusing a few topics.
First, the article you listed below has nothing to do with the API keys and filebeat.
That article refers to the user that Kibana uses to connect with Elasticsearch. In previous versions. You could use the elastic user but that's no longer an option.
So let's put that aside
Please always include the version of the stack you are working with... So what version are you on?
Now you should just log in as the elastic user and create the filebeat writer API key as defined in the documentation.
Then please show us how you're configuring file be with this API key...
And what command are you running when you get that error.
Were you running setup?
Or just trying to start filebeat.
If you created a new user with no roles that will probably not work as an API key is an intersection of the roles of the users that created it with the roles defined in the API key. I just wrote this up in another topic..
So log in with the elastic user and create the API key
Show us the versions
Show us the configuration
Show us the command you're running
And the result