It was because I have a paginated api and I commit on purpose an error when page is empty. Since iterator was not finishing, array aggregator cannot detect iterator as finished and hence output was never coming
therefore only solution is to let run the paginated api until it finishes
I just want to quickly say great job resolving this by yourself!
Thanks a lot for stepping back into the community and sharing what did the final trick for you. This is super valuable and could be incredibly helpful to many others who are looking for similar information.
FYI: I marked your comment as a solution to keep the community organized and easy to search for answers.