Manually publishing to pub/sub


I have an action which is defined much like this example: akkaserverless-wirelessmesh-java/publishing.proto at main · lightbend-labs/akkaserverless-wirelessmesh-java · GitHub

The difference is that, instead of subscribing on events of an event-sourced-entity, the action is called ‘manually’, from another component: I forward a command to it.
So, the definition doesn’t have an annotation, only an eventing.out.

The implementation of the publish-action is just a pass-through, just like in the example akkaserverless-wirelessmesh-java/ at main · lightbend-labs/akkaserverless-wirelessmesh-java · GitHub

When running this, I don’t see any errors, but there are no messages published on the topic.
I’m sure the action is called (there is a log-statement it it, which I can see in the logs).

(the topic is created and the service-account for it is there)
I also tried with calling the publish-action by means of an effect (instead of a forward), but that didn’t work either.

What could be missing?
Thanks you!