Could you please also provide an image from the page where you are configuring the parameters? Do you get any errors at the end of the setup?
Also I see that you have set the Authentication type to Basic. I'm not familiar with ElasticSearch API so would you please tell me how are you doing the authentication? The body seems to contain only the query and the inline parameter seems to serve only as an index.
It would be great if you could use Fiddler or another proxy tool to check the requests, their responses, and statuses. Please create a Fiddler trace (see how to create .SAZ file) and send it back to us. You could also create a video recording so that we can see exactly what is happening.