Same problem here; Eurotronic Spirit Zigbee + Conbee II + Raspberry Pi3B+. Additionally tried and failed to connect via deConz.
This is my first zigbee device, so I am wondering on which side is the issue: conbee, thermostat, or the software?
Gonna also try this during the weekend [SOLVED] ConBee II and Eurotronic Spirit Zigbee integration