It likely uses ZigBee Smart Energy Public Profile, which while it uses ZigBee, doesn't work with generic ZigBee receivers.

https://www.home-assistant.io/docs/energy/electricity-grid/#...

And here's some details on the specs if you want to dig in and see if it matches what you are seeing

https://zigbeealliance.org/wp-content/uploads/2019/11/docs-0...