Zigbee2MQTT - cannot open Web UI - 502 Bad Gateway

I have been using same config now for some months.
Nothing has been changed.

Since yesterday: I noticed that my lights where not available.
Restarted Z2MQTT, restarted the RPI4.
Nothing helps and I cannot use the Web UI: 502 Bad Gateway

Current version: 1.18.1-1
HA Core 9.7


Zigbee2MQTT:info  2021-10-01 15:33:28: Starting Zigbee2MQTT version 1.18.1 (commit #1.18.1)
Zigbee2MQTT:info  2021-10-01 15:33:28: Starting zigbee-herdsman (0.13.71)
Zigbee2MQTT:debug 2021-10-01 15:33:28: Using zigbee-herdsman with settings: '{"adapter":

2021-10-01T13:33:28.395Z zigbee-herdsman:adapter Failed to validate path: 'Error: spawn udevadm ENOENT'
Zigbee2MQTT:error 2021-10-01 15:33:47: Error while starting zigbee-herdsman
Zigbee2MQTT:error 2021-10-01 15:33:47: Failed to start zigbee
Zigbee2MQTT:error 2021-10-01 15:33:47: Exiting...
Zigbee2MQTT:error 2021-10-01 15:33:47: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
    at ZStackAdapter.<anonymous> (/app/node_modules/zigbee-herdsman/dist/adapter/z-stack/adapter/zStackAdapter.js:94:31)
    at Generator.throw (<anonymous>)
    at rejected (/app/node_modules/zigbee-herdsman/dist/adapter/z-stack/adapter/zStackAdapter.js:25:65)
npm ERR! errno 1
npm ERR! [email protected] start: `node index.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the [email protected] start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2021-10-01T13_33_48_021Z-debug.log

It’s not connecting to the ZigBee adapter.
Check the address of the adaptor on the hardware settings and make sure they match in Z2M.
If not unplug the stick and plug back in maybe in a different usb slot.

I already unplugged the stick. have not used another usb slot.
Address of the adaptor has been changed in the config.


port: >-


Device path:`/dev/ttyACM0`

Might be hardware failure then possibly the ZigBee stick or even the usb slot it’s plugged into.

I will try another usb slot first.
Do not have another adaptor/stick now to test.

If I change to another usb slot, does the address change?

Did you get this resolved?
Have the exact same issue…

Same error ?


  • Changed USB for ConBee II
  • Triple checked the device address.
  • user and pw are correct
  • server address is correct

Log and config bellow with Zigbee Herdsman debug logging enabled:

[s6-init] making user provided files available at /var/run/s6/etc...exited 0.
[s6-init] ensuring user provided files have correct perms...exited 0.
[fix-attrs.d] applying ownership & permissions fixes...
[fix-attrs.d] done.
[cont-init.d] executing container initialization scripts...
[cont-init.d] socat.sh: executing... 
[14:46:43] INFO: Socat not enabled, marking service as down
[cont-init.d] socat.sh: exited 0.
[cont-init.d] zigbee2mqtt.sh: executing... 
[14:46:44] INFO: MQTT available, fetching server detail ...
[14:46:44] INFO: Previous config file found, checking backup
[14:46:44] INFO: Creating backup config in '/config/zigbee2mqtt/.configuration.yaml.bk'
[14:46:44] INFO: Adjusting Zigbee2mqtt core yaml config with add-on quirks ...
[cont-init.d] zigbee2mqtt.sh: exited 0.
[cont-init.d] done.
[services.d] starting services
[services.d] done.
[14:46:45] INFO: Zigbee Herdsman debug logging enabled
[14:46:46] INFO: Handing over control to Zigbee2mqtt Core ...
> [email protected] start
> node index.js
2021-11-26T13:46:52.477Z zigbee-herdsman:adapter Failed to validate path: 'Error: spawn udevadm ENOENT'
2021-11-26T13:46:52.485Z zigbee-herdsman:controller:log Starting with options '{"network":{"networkKeyDistribute":false,"networkKey":[1,3,5,7,9,11,13,15,0,2,4,6,8,10,12,13],"panID":6754,"extendedPanID":[221,221,221,221,221,221,221,221],"channelList":[11]},"serialPort":{"path":"/dev/serial/by-id/usb-dresden_elektronik_ingenieurtechnik_GmbH_ConBee_II_DE2401204-if00"},"databasePath":"/config/zigbee2mqtt/database.db","databaseBackupPath":"/config/zigbee2mqtt/database.db.backup","backupPath":"/config/zigbee2mqtt/coordinator_backup.json","adapter":{"disableLED":false,"concurrent":null,"delay":null}}'
2021-11-26T13:46:52.487Z zigbee-herdsman:adapter:zStack:znp:log Opening SerialPort with /dev/serial/by-id/usb-dresden_elektronik_ingenieurtechnik_GmbH_ConBee_II_DE2401204-if00 and {"baudRate":115200,"rtscts":false,"autoOpen":false}
2021-11-26T13:46:52.498Z zigbee-herdsman:adapter:zStack:znp:log Serialport opened
2021-11-26T13:46:52.501Z zigbee-herdsman:adapter:zStack:znp:SREQ --> SYS - ping - {"capabilities":1}
2021-11-26T13:46:52.505Z zigbee-herdsman:adapter:zStack:unpi:writer --> frame [254,0,33,1,32]
2021-11-26T13:46:52.761Z zigbee-herdsman:adapter:zStack:znp:log Writing CC2530/CC2531 skip bootloader payload
2021-11-26T13:46:52.762Z zigbee-herdsman:adapter:zStack:unpi:writer --> buffer [239]
2021-11-26T13:46:53.766Z zigbee-herdsman:adapter:zStack:znp:SREQ --> SYS - ping - {"capabilities":1}
2021-11-26T13:46:53.768Z zigbee-herdsman:adapter:zStack:unpi:writer --> frame [254,0,33,1,32]
2021-11-26T13:46:54.019Z zigbee-herdsman:adapter:zStack:znp:log Skip bootloader for CC2652/CC1352
2021-11-26T13:46:54.479Z zigbee-herdsman:adapter:zStack:znp:SREQ --> SYS - ping - {"capabilities":1}
2021-11-26T13:46:54.480Z zigbee-herdsman:adapter:zStack:unpi:writer --> frame [254,0,33,1,32]
2021-11-26T13:47:00.486Z zigbee-herdsman:adapter:zStack:znp:SREQ --> SYS - ping - {"capabilities":1}
2021-11-26T13:47:00.488Z zigbee-herdsman:adapter:zStack:unpi:writer --> frame [254,0,33,1,32]
2021-11-26T13:47:06.492Z zigbee-herdsman:adapter:zStack:znp:SREQ --> SYS - ping - {"capabilities":1}
2021-11-26T13:47:06.493Z zigbee-herdsman:adapter:zStack:unpi:writer --> frame [254,0,33,1,32]
Zigbee2MQTT:error 2021-11-26 14:47:12: Error while starting zigbee-herdsman
Zigbee2MQTT:error 2021-11-26 14:47:12: Failed to start zigbee
Zigbee2MQTT:error 2021-11-26 14:47:12: Check https://www.zigbee2mqtt.io/information/FAQ.html#help-zigbee2mqtt-fails-to-start for possible solutions
Zigbee2MQTT:error 2021-11-26 14:47:12: Exiting...
Zigbee2MQTT:error 2021-11-26 14:47:12: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
    at ZStackAdapter.start (/app/node_modules/zigbee-herdsman/src/adapter/z-stack/adapter/zStackAdapter.ts:102:27)
    at Controller.start (/app/node_modules/zigbee-herdsman/src/controller/controller.ts:123:29)
    at Zigbee.start (/app/lib/zigbee.ts:58:27)
    at Controller.start (/app/lib/controller.ts:100:27)
    at start (/app/index.js:97:5)
data_path: /config/zigbee2mqtt
external_converters: []
devices: devices.yaml
groups: groups.yaml
homeassistant: true
permit_join: false
  base_topic: zigbee2mqtt
  server: mqtt://
  user: mqtt_user
  password: mqtt_pass
  port: >-
  log_level: warn
  pan_id: 6754
  channel: 11
    - 1
    - 3
    - 5
    - 7
    - 9
    - 11
    - 13
    - 15
    - 0
    - 2
    - 4
    - 6
    - 8
    - 10
    - 12
    - 13
  availability_blocklist: []
  availability_passlist: []
device_options: {}
blocklist: []
passlist: []
queue: {}
  port: 8099
experimental: {}
availability: false
  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
zigbee_herdsman_debug: true

I even re-flashed the whole hassio :slight_smile: