Error: Connection refused: Not authorized

Hello,

I am getting stuck with error message as follows:

Error: Connection refused: Not authorized
    at MqttClient._handleConnack (/usr/lib/node_modules/mqtt/lib/client.js:920:15)
    at MqttClient._handlePacket (/usr/lib/node_modules/mqtt/lib/client.js:350:12)
    at work (/usr/lib/node_modules/mqtt/lib/client.js:292:12)
    at Writable.writable._write (/usr/lib/node_modules/mqtt/lib/client.js:302:5)
    at doWrite (/usr/lib/node_modules/readable-stream/lib/_stream_writable.js:428:64)
    at writeOrBuffer (/usr/lib/node_modules/readable-stream/lib/_stream_writable.js:417:5)
    at Writable.write (/usr/lib/node_modules/readable-stream/lib/_stream_writable.js:334:11)
    at Socket.ondata (_stream_readable.js:693:20)
    at Socket.emit (events.js:189:13)
    at addChunk (_stream_readable.js:288:12)
    at readableAddChunk (_stream_readable.js:269:11)
    at Socket.Readable.push (_stream_readable.js:224:10)
    at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:145:17)

Tried already with two different mqtt servers, and the outcome is still the same. Would you have any idea, what do I do wrong?

Xiaomi Xiaofang cam, tried mqtt in Homebridge (RPi) and on Synology NAS, 

mqtt.conf:

# Options for mosquitto_sub & mosquitto_pub
USER="homebridge"
PASS="homebridge"
HOST=10.10.0.10
PORT=1883


config.json:
  {
            "platform": "Dafang",
            "mqtt": {
                "hostBroker": false,
                "port": 1883,
                "host": "10.10.0.10",
                "debug": true
            },
            "cameras":

