Look at the URL of the Unifi controller:
https://192.168.2.X:8443/manage/xxxxxxxxx/dashboard

fill in what's behind manage and dashboard. So in this case fill in: xxxxxxxx

It works!

I entered the wrong Unifi Sitename

Thanks Watervl! I downgraded my Pi to Raspbian Buster, and now, I can see in the domoticz log, the plugin is running
But, It's not detecting a connected phone.

I read that the Unifi setup of Wizzard 72 was with a Unifi Gateway. Is that neccesary for the the plugin to work?

Is there anyone else who has the solution?

The installation of the Ubiquiti Unifi Presence Plugin works smoothly, using the instructions of Wizzard 72 supplied. But when I add the plugin as new hardware, my Domoticz stops running. The webpage freezes and nothing works any more.

In the Domoticz log ...

Hi Wizzard 72,

I think your Unifi plugin is very useful for my Domoticz Home Automation!
The installation works smoothly, using your instructions. But when I add the plugin as new hardware, my Domoticz stops running. The webpage freezes and nothing works any more.

The only way to get Domitcz ...