Here is the Ewon MQTT broker. This MQTT broker can be used to test the MQTT connection using your Ewon Flexy.
To configure the MQTT connection in your Flexy, you can simply use this example.
Just copy/paste it into your BASIC Init section and run the script. Make sure the Internet connection is well configured and the TCP port 1883 is open on your local network.
Here below you can see the messages sent by your Ewon Flexy. Type the topic to monitor and click "Start". You will then see all messages published to the this topic during 60 seconds.
Let the topic field blank if you want to monitor all topics.
Here you can publish a message to a topic, the same way as the Flexy does :
If the Flexy has subscribed to the same topic, it should also get this message. This way, you can send commands to your Flexy remotely.