Making an MQTT cover, entity unavailable

Hi, I’m looking to use the MQTT cover function for a shelly 2.5. It’s connected through MQTT. This is my configuration.yaml

    cover:
    - unique_id: "DakraamBadkamer"
      name: "DakraamBadkamer"
      qos: 1
      #retain: true
      command_topic: "shellies/shellyswitch25-C8C9A3741BA6/roller/0/command"
      payload_open: "open"
      payload_close: "close"
      payload_stop: "stop"
      
      state_topic: "shellies/shellyswitch25-C8C9A3741BA6/roller/0"
      state_opening: "open"
      state_open: "opened" #won't be reported from Shelly, but at least it deviates from open
      state_closing: "close"
      state_closed: "closed" #won't reported from Shelly, but at least it deviates from close

      #needs to be configured to rely on position if stopped:
      state_stopped: "stop"
      
      availability:
       - topic: "shellies/shellyswitch25-C8C9A3741BA6/online"
      payload_available: "true"
      payload_not_available: "false"

      position_topic: "shellies/shellyswitch25-C8C9A3741BA6/roller/0/pos"

      set_position_topic: "shellies/shellyswitch25-C8C9A3741BA6/roller/0/command/pos"

      optimistic: false

However, the entity shows up as unavailable. I have checked with MQTT explorer and shellies/shellyswitch25-C8C9A3741BA6/online reports as true. Who can help me with what I’m doing wrong here? :slightly_smiling_face: