Dynamic input for select box

I am trying to fill the select values with dynamic values from my spring boot application. I set the variables to a hashmap and returning it to camunda run, but every time the select box in the form shows no entries.
I am using the delegate execution and returning like described in the docs.
I can’t find any Description of how to set the field in the modeler properly. This is what i tried:

Am i doing anything wrong? Pls help me.