A16 - MQTT Issues

[PierrePetite]

Hey, 

first of all: Thanks for this great product! I am now trying to connect it via MQTT to Home Assistant. (I had several issues by using ESPHome, so I wanna stick with MQTT for now). 

What I did: 

• MQTT Setup within KCS
  
• Setup Mosquito and MQTT within Home-Assistant (Already existing)
  
• Confirmed that the Packages are received by listening to #
  

I have used the following YAML within Home Assistants configuration.yaml, customized based on the received packages while listening to #:

Code:

mqtt:
  switch:
   - name: 'kcs868-a16-output-1'
     unique_id: kcs868-a16-output-1
     state_topic: 'KC868_A16/2CBCBB646ACC/STATE'
     command_topic: 'KC868_A16/2CBCBB646ACC/SET'
     payload_on:  '{"output1":{"value":true}}'
     payload_off:  '{"output1":{"value":false}}'
     value_template: '{{ value_json.output1.value }}'
     state_on: true
     state_off: false

As a result, I can - after restarting Home Assistant control the Output 1. 
BUT: It does not show the current status of Output one! (See Screenshot). Status is unknown. 

Any Idea what went wrong? What could I check?