Zigbee2MQTT fails to connect to SMLIGHT SLZB-06P7

Configuration Zigbee
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1

I’ve been running Zigbee2MQTT on Home Assistant OS (Raspberry Pi 5, Zigbee2MQTT add-on, Mosquitto add-on).
Coordinator: SMLIGHT SLZB-06P7

  • SLZB-OS firmware: v2.9.8
  • Zigbee radio firmware: 20240315

It worked fine for months. Since the recent SMLIGHT firmware, Zigbee2MQTT fails to start and I get:

Error: SRSP - SYS - ping after 6000ms
Failed to connect to the adapter
  • ZHA is not installed.
  • The SLZB is reachable: nc 192.168.178.94 6638 → open.
  • MQTT broker is working fine, other integrations publish normally. In MQTT Explorer I still see retained Zigbee2MQTT topics, but zigbee2mqtt/bridge/state stays offline.

Config:

data_path: /config/zigbee2mqtt
socat:
  enabled: false
  master: pty,raw,echo=0,link=/tmp/ttyZ2M,mode=777
  slave: tcp-listen:8485,keepalive,nodelay,reuseaddr,keepidle=1,keepintvl=1,keepcnt=5
  options: "-d -d"
  log: false
mqtt:
  server: mqtt://core-mosquitto:1883
  user: MyUser
  password: MyPass123
serial:
  port: tcp://192.168.178.94:6638
  baudrate: 115200
  adapter: zstack
  disable_led: false
advanced:
  transmit_power: 20

Has anyone else run into this with the SLZB-06P7 after recent firmware?
Should I keep using direct TCP, or is switching to socat the only stable option?

2

Can you connect to the SMLight UI with the device’s IP?

3

Yes, the SMLight UI is reachable.

4

Verify the mode is coordinator and the connection is still WiFi or ethernet.

Can you post a larger portion of your Z2M log showing before and after the error?

5

The connection is still over LAN:
image

The mode is coordinator:

image
image739×479 23.4 KB

These are the only logs that I have left:

[11:40:08] INFO: Preparing to start...
[11:40:08] INFO: Socat not enabled
[11:40:08] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.
[2025-08-26 11:40:29] error: 	z2m: Error while starting zigbee-herdsman
[2025-08-26 11:40:29] error: 	z2m: Failed to start zigbee-herdsman
[2025-08-26 11:40:29] error: 	z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2025-08-26 11:40:29] error: 	z2m: Exiting...
[2025-08-26 11:40:29] error: 	z2m: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
    at ZStackAdapter.start (/app/node_modules/.pnpm/[email protected]/node_modules/zigbee-herdsman/src/adapter/z-stack/adapter/zStackAdapter.ts:114:27)
    at Controller.start (/app/node_modules/.pnpm/[email protected]/node_modules/zigbee-herdsman/src/controller/controller.ts:134:29)
    at Zigbee.start (/app/lib/zigbee.ts:67:27)
    at Controller.start (/app/lib/controller.ts:101:13)
    at start (/app/index.js:149:5)
6

Z2M is failing immediately with no attempt to open the port to connect. What version of Z2M are you using?

I would expect this :arrow_down:
Opening TCP socket with 192.168.xx.xx:6638

Try a full reboot, not just a restart.

7

I have auto updates on. My current version is: 2.6.0-1

I just fully rebooted my Raspberry Pi, but still getting the same error.

8

I am experiencing the exact same thing. Very strange.

[00:37:47] INFO: Preparing to start...
[00:37:47] INFO: Socat not enabled
[00:37:47] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.
[2025-08-27 00:38:07] error: 	z2m: Error while starting zigbee-herdsman
[2025-08-27 00:38:07] error: 	z2m: Failed to start zigbee-herdsman
[2025-08-27 00:38:07] error: 	z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2025-08-27 00:38:07] error: 	z2m: Exiting...
[2025-08-27 00:38:07] error: 	z2m: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
    at ZStackAdapter.start (/app/node_modules/.pnpm/[email protected]/node_modules/zigbee-herdsman/src/adapter/z-stack/adapter/zStackAdapter.ts:114:27)
    at Controller.start (/app/node_modules/.pnpm/[email protected]/node_modules/zigbee-herdsman/src/controller/controller.ts:134:29)
    at Zigbee.start (/app/lib/zigbee.ts:67:27)
    at Controller.start (/app/lib/controller.ts:101:13)
    at start (/app/index.js:149:5)```
9

After reflashing the firmware to 20240710, setting the whitelist on the webui of the adapter, rebooting and than disabling the whitelist again, I can report that the connection did work again. Also I rebooted the adapter and HA. Not sure what steps actually made the connection work again.

10

I am just experiencing the same exactly thing.
My coordinator stopped working in one the the HA version upgrades and I can not make my coordinator start working again

11

I change the fimrware and went back from v3.0.8 to v2.8.7 just to see if that works.