I don't know what happened but it is working now. Unfortunately, I do not know the cause ..
But thanks again for the flow. Works great!

Hi Emme, Thanks for your flow! I've installed Node-RED and MQTT and imported your flow. Thereafter I've put in al the right variables and I got the notification 'connected' on MPD and domoticz, but no signs go to Domoticz. I ain't see anything in the log. Did I forgot something? Do I have to do ...

I was also struggling with this doorbell. Domoticz wouldn't recognize it. In my case I needed also to enable Lighting4. Just for your information.