Conbee unstable

Hi there,

I did some searching but could not find any solution for so far.

I have HA running on Proxmox, with Zwave, RFXcom and a conbee2 stick.
But the conbee 2 stick runs for a couple of days, and then suddenly stops responding. I need to reboot my proxmox machine to bring it back online. In the hardware tab of the Proxmox machine, the hardware is still there.
Most of the time i need to reconfigure my Zigbee devices than again in HA.

Latest log from today from HA is:
Lost serial connection: device reports readiness to read but returned no data (device disconnected or multiple access on port?

I have this problem as well for the last 2 months. Supervised HA on ubuntu. All zigbee devices stop responding; rebooting the ubuntu, or simply disconnecting and connecting back the conbee stick without rebooting solves the problem and everything works again. Nothing else to be done. Didn’t checked the logs, had this problem 3 times in this 2 months.

Is the conbee firmware on the stick up to date?

just checked, i was runinng 1 version behind, did an update, so let’s see how stable it is now.

Strange thing is, it is working now for the moment, but I got this warning now every 10 minutes in my log:

and after a restart from the HA the zigbee is gone again…

Logger: zigpy_deconz.api
Source: /usr/local/lib/python3.9/site-packages/zigpy_deconz/
First occurred: 11:27:15 AM (4 occurrences)
Last logged: 11:38:49 AM

Serial ‘/dev/serial/by-id/usb-dresden_elektronik_ingenieurtechnik_GmbH_ConBee_II_DE2407496-if00’ connection lost unexpectedly: device reports readiness to read but returned no data (device disconnected or multiple access on port?)

  • extended log -
    Logger: homeassistant.components.zha.core.gateway
    Source: components/zha/core/
    Integration: Zigbee Home Automation (documentation, issues)
    First occurred: 11:27:07 AM (1 occurrences)
    Last logged: 11:27:07 AM

Couldn’t start deCONZ = dresden elektronik deCONZ protocol: ConBee I/II, RaspBee I/II coordinator

Traceback (most recent call last): File “/usr/local/lib/python3.9/site-packages/serial/”, line 322, in open self.fd =, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK) OSError: [Errno 5] I/O error: ‘/dev/serial/by-id/usb-dresden_elektronik_ingenieurtechnik_GmbH_ConBee_II_DE2407496-if00’ During handling of the above exception, another exception occurred: Traceback (most recent call last): File “/usr/src/homeassistant/homeassistant/components/zha/core/”, line 152, in async_initialize self.application_controller = await File “/usr/local/lib/python3.9/site-packages/zigpy/”, line 69, in new await app.startup(auto_form) File “/usr/local/lib/python3.9/site-packages/zigpy_deconz/zigbee/”, line 66, in startup await self._api.connect() File “/usr/local/lib/python3.9/site-packages/zigpy_deconz/”, line 245, in connect self._uart = await zigpy_deconz.uart.connect(self._config, self) File “/usr/local/lib/python3.9/site-packages/zigpy_deconz/”, line 142, in connect _, protocol = await serial_asyncio.create_serial_connection( File “/usr/local/lib/python3.9/site-packages/serial_asyncio/”, line 445, in create_serial_connection serial_instance = serial.serial_for_url(*args, **kwargs) File “/usr/local/lib/python3.9/site-packages/serial/”, line 90, in serial_for_url File “/usr/local/lib/python3.9/site-packages/serial/”, line 325, in open raise SerialException(msg.errno, “could not open port {}: {}”.format(self._port, msg)) serial.serialutil.SerialException: [Errno 5] could not open port /dev/serial/by-id/usb-dresden_elektronik_ingenieurtechnik_GmbH_ConBee_II_DE2407496-if00: [Errno 5] I/O error: '/dev/serial/by-id/usb-dresden_elektronik_ingenieurtechnik_GmbH_ConBee_II_DE2407496-if00

There are reports that if it is connected to a USB3 port it can act strangely (use a USB2 hub in between) and/or is the stick is used with a USB length cable it works better… worth trying.

I have an usb extension cable in between, still have the unstable issue.

I have ordered a new powered USB 2.0 hub, going to test with that.