Thanks AllesVanZelf, that did it. Just how did you know to select 'OpenZwave' device for an Aeotec Z-Stick Gen5+?

Where do I specify the serial port to use? 'Setup'>'Hardware' does not mention the Z-Stick.

My understanding is that the Z-Stick Gen5+ fixed the problem that was with the Z-Stick Gen5. Maybe I am wrong?

I'm a complete beginner! Hardware: Raspberry Pi4B running Raspberry PI OS (Buster), Aeotec Z-Stick Gen5+, Domoticz Version: 2021.1 It is a new install of the Raspberry Pi OS, and I have download Domoticz and installed it, I have have the Z-Stick Gen5+ plugged into a USB port of the Pi (tried both ...