I populate the groupId, the DataflowID as parameters, and set the body as:
The objective being to get a notifcation (email) once the refresh is done, wether it's a success or a failure.
When I do this, the refresh is triggered as expected, but I never receive the email once it's done. I've tried on Dataflows that voluntary have a fail refresh, or working; with "MailOnCompletion" or "MailOnFailure", but it never worked.
I tried on Postman as well, and directly and finally on the "Try it" feature from the documentation, as shown on the screenshot: