I succeeded in starting domoticz again by deleting the device in the domoticz.db.
I tried to add another switch with the green arrow from the devices table (another bulb) and when I change the status of the switch (dim or on/off), domoticz crashed again with seg fault.
I really don't understand ...

Hi moroen, I had the same error than andi2016 : python3 tradfri.tac produces for group in self.groups: builtins.TypeError: 'Group' object is not iterable Disconnected coap-client -k xxx coaps://192.168.1.108/15004/ returns v:1 t:CON c:GET i:c822 {} [ ] [159174] and coap-client -k xxx coaps://192.168 ...