Z2MQTT suddenly stopped working and wont start -Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)

Configuration Zigbee
1

My install of Z2mQTT has suddenly stopped working and no zigbee devices are operating. MQTTT is running and I cant see any particular errors. I have done nothing to my install other than install the recent core update.

2

I’ve had another look this morning and z2m wasnt running, when i try and start it it fails with errors regarding not being able to connect to coordinator

[07:36:57] INFO: Preparing to start...
[07:36:57] INFO: Socat not enabled
[07:36:57] INFO: Enabled Zigbee2MQTT watchdog with value 'default'
[07:36:58] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT with watchdog (2000,60000,300000,900000,1800000,3600000).
[2026-03-28 07:37:01] info: 	z2m: Logging to console, file (filename: log.log)
[2026-03-28 07:37:01] info: 	z2m: Starting Zigbee2MQTT version 2.9.1 (commit #unknown)
[2026-03-28 07:37:01] info: 	z2m: Starting zigbee-herdsman (9.0.9)
[2026-03-28 07:37:01] info: 	zh:zstack:znp: Opening TCP socket with 10.0.0.75:6638
[2026-03-28 07:37:01] info: 	zh:zstack:znp: Socket connected
[2026-03-28 07:37:01] info: 	zh:zstack:znp: Socket ready
[2026-03-28 07:37:01] info: 	zh:zstack:znp: Writing CC2530/CC2531 skip bootloader payload
[2026-03-28 07:37:02] info: 	zh:zstack:znp: Skip bootloader for CC2652/CC1352
[2026-03-28 07:37:20] error: 	z2m: Error while starting zigbee-herdsman
[2026-03-28 07:37:20] error: 	z2m: Failed to start zigbee-herdsman
[2026-03-28 07:37:20] error: 	z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2026-03-28 07:37:20] error: 	z2m: Exiting...
[2026-03-28 07:37:20] 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:107:27)
    at Controller.start (/app/node_modules/.pnpm/[email protected]/node_modules/zigbee-herdsman/src/controller/controller.ts:145:29)
    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)

The coordinator has a static IP and is still reachable on the network at the old address so have no idea what stopping z2m from seeing it. Any suggestions what I should check in Z2m settings?

3

RESOLVED
Just in case anyome else has this issue and comesacross my post I have now fixed it.
I upgraded the firmware on the SLZB-06 coordinator. I was on 20221226 v2.9.5 which appears to be quite old and a long way behind Koenkk’s stable 20250321 version.
Updating and then rebooting the coordinator and Home Assistant PC resulted in Z2M starting without errors and the majority of my devices are now working again. there are a couple that need re-pairing but its a relief to have control of my devices again. As an aside a couple of Tuya devices, which were in the supported database, onboard before with automatically generated definitions. Now they have been properly recognised and functional.
I dont know if the old firmware was somehow corrupt or just out of date for ZTM v2.9.1
A lesson learned :wink:

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