Zigbee radio down or pairing fails

RADIO DOWN, MQTT OFFLINE, crash-looping coordinator, the wrong stick firmware (Thread vs Zigbee), permit-join not taking, and why not to wipe the pairing database.

Read this first

Do not wipe the Zigbee database or re-form the network to fix one device. That unpairs everything. Factory-reset only the misbehaving end device.

1. Is SkyConnect plugged into a USB 2 port? Over SSH, ls -l /dev/ttyACM0 (or the by-id path) must exist.
2. Is the coordinator container running? docker ps -a --filter name=z2m. A crash loop with HOST_FATAL_ERROR in docker logs means the stick's firmware does not match the driver.
3. The stick may be running OpenThread firmware rather than Zigbee NCP (a known state for some SkyConnects). Probe it with universal-silabs-flasher --device <by-id> probe and flash the Zigbee NCP firmware. After a Thread → Zigbee flash the coordinator forms a new network: previously paired devices must be factory-reset and paired again.
4. Soft-restart only the coordinator: docker stop -t 20 <z2m> then docker start <z2m>.

The internal message bus is down. docker ps should show the mosquitto container; restart it the same way. The brain reconnects on its own.

• JOIN OPEN must be showing; it lasts about four minutes, re-press it.
• The device must be in pairing mode (LED blinking). A device that was on another network needs a factory reset on the device.
• Watch the bus: mosquitto_sub -h 127.0.0.1 -t 'zigbee2mqtt/+' -v shows the join if the radio hears it.
• Range: pair within a few metres of the stick, then move the device.

• Battery devices report on change and on a heartbeat; wait, or trigger the sensor.
• An Unbound row feeds nothing. Open the device, say where it lives (a temperature / humidity sensor: Zone, then Placement, then an optional Position; anything else: Role and Zone) and Save.
• A smoke, gas or CO alarm that stops checking in raises Safety alarm silent (warn) after 26 hours. Check its battery and press its test button; if it still does not report, re-pair it and bind it to its role again.
• Some leak sensors report wet as occupancy; that is expected.

Bindings and roles are retained across restarts. If they are gone, restore the last backup (it includes the Zigbee data).

Guide contents  ·  Troubleshooting  ·  Troubleshooting  ·  Digital Stealth Care

DSC-Brain user guide · Zigbee radio down or pairing fails · this page is edited on the site; the Notion original was retired after the mirror