I am using hassio with the integreated mosquito broker, now I installed the zigbee2mqtt add-on, it works, sensors are publishing to topic zigbee2mqtt and zigbee2mqtt is announcing the sensors to topic homeassistant for discovery.
after adding
mqtt:
discovery: true
discovery_prefix: homeassistant
to configuration.yaml and restarting I get this errors:
Unable to prepare setup for platform mqtt.sensor: Unable to set up component.
Setup failed for mqtt: Integration failed to initialize.
Unable to start embedded MQTT broker
Error initializing MQTT server
Broker startup failed: [Errno 98] error while attempting to bind on address (‘0.0.0.0’, 1883): address in use