MQTT failed to connect, exiting... (connack timeout)

[pace8828]

Hey folks, I've tried to set up Z2M on multiple occasions but I continue to get this error every time. I have Mosquitto and Z2M configured in the same Docker Compose file, and I can connect to my MQTT broker just fine with MQTT Explorer. I've searched everywhere but couldn't find anything that helped.

Z2M log with connack timout error:

[2025-09-07 11:58:49] info: 	z2m: Logging to console, file (filename: log.log)
[2025-09-07 11:58:49] info: 	z2m: Starting Zigbee2MQTT version 2.6.1 (commit #e9889e5d20e8911550d5231bc0349567cc2bb9ce
)
[2025-09-07 11:58:49] info: 	z2m: Starting zigbee-herdsman (6.0.4)
[2025-09-07 11:58:49] info: 	zh:zstack:znp: Opening TCP socket with 192.168.68.104:6638
[2025-09-07 11:58:49] info: 	zh:zstack:znp: Socket connected
[2025-09-07 11:58:49] info: 	zh:zstack:znp: Socket ready
[2025-09-07 11:58:49] info: 	zh:zstack:znp: Writing CC2530/CC2531 skip bootloader payload
[2025-09-07 11:58:50] info: 	zh:zstack:znp: Skip bootloader for CC2652/CC1352
[2025-09-07 11:59:16] info: 	zh:controller: Wrote coordinator backup to '/app/data/coordinator_backup.json'
[2025-09-07 11:59:17] info: 	z2m: zigbee-herdsman started (reset)
[2025-09-07 11:59:17] info: 	z2m: Coordinator firmware version: '{"meta":{"maintrel":1,"majorrel":2,"minorrel":7,"product":1,"revision":20240710,"transportrev":2},"type":"ZStack3x0"}'
[2025-09-07 11:59:17] info: 	z2m: Currently 0 devices are joined.
[2025-09-07 11:59:17] info: 	z2m: Connecting to MQTT server at mqtt://192.168.68.102:1883
[2025-09-07 11:59:47] error: 	z2m: MQTT failed to connect, exiting... (connack timeout)
[2025-09-07 11:59:47] info: 	z2m: Stopping zigbee-herdsman...

Z2M "configuration.yaml":

version: 4
mqtt:
  base_topic: zigbee2mqtt
  server: mqtt://192.168.68.102:1883
serial:
  port: tcp://192.168.68.104:6638
  adapter: zstack
  baudrate: 115200
  rtscts: false
advanced:
  log_level: info
  channel: 25
  network_key:
    - 157
    - 220
    - 49
    - 252
    - 160
    - 10
    - 231
    - 83
    - 132
    - 219
    - 35
    - 122
    - 32
    - 115
    - 77
    - 54
  pan_id: 21643
  ext_pan_id:
    - 246
    - 249
    - 49
    - 108
    - 233
    - 169
    - 155
    - 96
frontend:
  enabled: true
  port: 8080
homeassistant:
  enabled: true
onboarding: true

"mosquitto.conf"

listener 1883
listener 9001
protocol websockets
allow_anonymous true
persistence true
persistence_file mosquitto.db
persistence_location /mosquitto/data/
log_dest file /mosquitto/log/mosquitto.log
log_dest stdout
log_type all

Docker "compose.yaml":

mosquitto:
    image: eclipse-mosquitto:latest
    container_name: mosquitto
    volumes:
      - /opt/docker/mosquitto/config:/mosquitto/config
      - /opt/docker/mosquitto/data:/mosquitto/data
      - /opt/docker/mosquitto/log:/mosquitto/log
    ports:
      - 1883:1883
      - 9001:9001
    stdin_open: true
    tty: true

  zigbee2mqtt:
        container_name: zigbee2mqtt
        image: ghcr.io/koenkk/zigbee2mqtt:latest
        restart: unless-stopped
        volumes:
            - /opt/docker/zigbee2mqtt/data:/app/data
            - /run/udev:/run/udev:ro
        ports:
            # Frontend port
            - 8080:8080