Minimal authentication for external task worker with basic auth

My engine rest is secured, my users and groups are mapped via ldap. I use basic-auth user/passwd for my worker. I am able to connect but get no tasks executed.
I suppose I have to authorize the user (resp. group) of my basic-auth account. But what categories are the minimal required? task? definition? … thanks!

An off topic reply which could however help getting real answers: are you sure you wanted to ask about the authentication and not authorization?

Well, I get your point … I am referring to the camunda cockpit tab “authentication” … where I set the (potentially 21) authentications for users and groups.