Hello Tamadite,
I think the problem is that you capitalize the K of the group name.
If you are using the newest version of z2m you can use the build in frondend https://www.zigbee2mqtt.io/information/frontend.html
Be sure to use a Zigbee2mqtt group, and not a HA group or HA light group. And I think you put your lights in a group, and then bind a remote/switch/motion sensor/whatever to it, but you don’t bind lights to a group.