Want to connect to Fibaro-switch via IUNGO energy meter

App version: latest
Phone OS: Android
Problem description:

I have an IUNGO energy metering system - I can program a switch to ON/OF.
I tried this with an API-tester (Talend API tester) - works like a charm.
I want to do the same with Olisto using a button so I configured the following:


BODY (JSON) for off:

BODY (JSON) for on:

What could be the issue?