Zigbee2MQTT fails to connect to SMLIGHT SLZB-06P7

f6vhef4 · August 26, 2025, 9:08am

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?

LiQuid_cOOled · August 26, 2025, 9:16am

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

f6vhef4 · August 26, 2025, 9:19am

Yes, the SMLight UI is reachable.

LiQuid_cOOled · August 26, 2025, 9:22am

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?

f6vhef4 · August 26, 2025, 9:41am

The connection is still over LAN:

The mode is coordinator:

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)

LiQuid_cOOled · August 26, 2025, 10:01am

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

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

Try a full reboot, not just a restart.

f6vhef4 · August 26, 2025, 9:47pm

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.

chhofi · August 26, 2025, 10:42pm

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)```

chhofi · August 26, 2025, 11:25pm

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.

avellma · October 24, 2025, 1:23am

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

avellma · October 24, 2025, 1:25am

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

tgechev · May 20, 2026, 7:44am

I now see the very same issue with the same device SLZB-06P7.

SLZB core firmware: v3.3.1
SLZB zigbee firmware: 20240716
Zigbee2MQTT version: 2.10.1

I also noticed this has occurred after a HA update. Zigbee2MQTT was down. The coordinator reported uptime of 25d+ and was reachable via its Web UI. Tried rebooting both Zigbee2MQTT and the coordinator - issue is still present. I do see the Opening TCP socket with 192.168.xx.xx:6638 log in the beginning. Initially the socket is created and it gets connected which is also confirmed by the logs in the coordinator's Web UI page. So for some reason it fails after establishing the socket connection...

Zigbee2MQTT log:

[10:29:00] INFO: Preparing to start...
[10:29:00] INFO: Socat not enabled
[10:29:00] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.
[2026-05-20 10:29:02] debug: 	z2m: Removing old log directory '/config/zigbee2mqtt/log/2026-05-20.10-00-58'
[2026-05-20 10:29:02] info: 	z2m: Logging to console, file (filename: log.log)
[2026-05-20 10:29:02] debug: 	z2m: Loaded state from file /config/zigbee2mqtt/state.json
[2026-05-20 10:29:02] info: 	z2m: Starting Zigbee2MQTT version 2.10.1 (commit #unknown)
[2026-05-20 10:29:02] info: 	z2m: Starting zigbee-herdsman (10.0.7)
[2026-05-20 10:29:02] debug: 	z2m: Using zigbee-herdsman with settings: '"{\"network\":{\"panID\":xxxxx,\"extendedPanID\":[xxx,xxx,xxx,xx,xxx,xxx,xxx,235],\"channelList\":[11],\"networkKey\":\"HIDDEN\"},\"databasePath\":\"/config/zigbee2mqtt/database.db\",\"databaseBackupPath\":\"/config/zigbee2mqtt/database.db.backup\",\"backupPath\":\"/config/zigbee2mqtt/coordinator_backup.json\",\"serialPort\":{\"baudRate\":115200,\"path\":\"tcp://192.168.xx.xxx:6638\",\"adapter\":\"zstack\"},\"adapter\":{\"disableLED\":false}}"'
[2026-05-20 10:29:02] debug: 	zh:controller: Starting with options '{"network":{"networkKeyDistribute":false,"networkKey":"HIDDEN","extendedPanID":[xxx,xxx,xxx,xx,xxx,xxx,xxx,235],"panID":xxxxx,"channelList":[11]},"serialPort":{"baudRate":115200,"path":"tcp://192.168.xx.xxx:6638","adapter":"zstack"},"adapter":{"disableLED":false},"databasePath":"/config/zigbee2mqtt/database.db","databaseBackupPath":"/config/zigbee2mqtt/database.db.backup","backupPath":"/config/zigbee2mqtt/coordinator_backup.json"}'
[2026-05-20 10:29:02] info: 	zh:zstack:znp: Opening TCP socket with 192.168.xx.xxx:6638
[2026-05-20 10:29:02] info: 	zh:zstack:znp: Socket connected
[2026-05-20 10:29:02] info: 	zh:zstack:znp: Socket ready
[2026-05-20 10:29:02] info: 	zh:zstack:znp: Writing CC2530/CC2531 skip bootloader payload
[2026-05-20 10:29:02] debug: 	zh:zstack:unpi:writer: --> buffer [239]
[2026-05-20 10:29:03] info: 	zh:zstack:znp: Skip bootloader for CC2652/CC1352
[2026-05-20 10:29:03] debug: 	zh:zstack:znp: --> SREQ: SYS - ping - {"capabilities":1}
[2026-05-20 10:29:03] debug: 	zh:zstack:unpi:writer: --> frame [254,0,33,1,32]
[2026-05-20 10:29:09] debug: 	zh:zstack:znp: --> SREQ: SYS - ping - {"capabilities":1}
[2026-05-20 10:29:09] debug: 	zh:zstack:unpi:writer: --> frame [254,0,33,1,32]
[2026-05-20 10:29:15] debug: 	zh:zstack:znp: --> SREQ: SYS - ping - {"capabilities":1}
[2026-05-20 10:29:15] debug: 	zh:zstack:unpi:writer: --> frame [254,0,33,1,32]
[2026-05-20 10:29:21] error: 	z2m: Error while starting zigbee-herdsman
[2026-05-20 10:29:21] error: 	z2m: Failed to start zigbee-herdsman
[2026-05-20 10:29:21] error: 	z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2026-05-20 10:29:21] error: 	z2m: Exiting...
[2026-05-20 10:29:21] 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:95:27)
    at Controller.start (/app/node_modules/.pnpm/[email protected]/node_modules/zigbee-herdsman/src/controller/controller.ts:146:29)
    at Zigbee.start (/app/lib/zigbee.ts:70:27)
    at Controller.start (/app/lib/controller.ts:111:29)
    at start (/app/index.js:156:5)

SLZB log:

[20.05.2026 10:29:02] SocketServer | [CC2652P7] New client, id: 0
[20.05.2026 10:29:21] SocketServer | [CC2652P7] Client disconnected, id: 0
[20.05.2026 10:29:28] SSE | new client: 192.168.x.xxx

LiQuid_cOOled · May 20, 2026, 8:11am

Is 20240716 Beta? I thought the released version was 20240710

tgechev · May 20, 2026, 8:24am

You are right! Oddly, the smlight HA integration reported the firmware channel as Stable even though the installed firmware was a dev release. Honestly, I cannot remember the last time I updated it. However, now switching to 20240710 brought Z2M back to life.

LiQuid_cOOled · May 20, 2026, 8:26am

Happy to assist! Beta versions can be finicky...