Commissioning matter/thread devices no longer works.
So I have 4 ikea matter devices (grillplats) working all working great for a couple of weeks.
Today I wanted to add more devices but commissioning no longer works, the existing devices do still work.
The setup:
Debian Trixie (13)
the following docker containers all in host network mode:
- openthread/border-router
- Package python-matter-server · GitHub
- homeassistant/home-assistant:2026.5.4
With an sonoff zbdongle-e flashed with the latest thread firmware
My router is a zyxel EX5601-T1
Commissioning is done using a google pixel 6a phone.
Commissioning both with the half-screen pop-up and via the companion app -> add device both give the same results:
Connecting to device -> Generating matter credentials -> Checking connectivity to Thread network [My network] --> Error message: "Can't reach device, make sure your phone is connected to wi-fi".
What I've tried:
- Ensure I'm on the same wifi network,
- Disable 4G
- Clear the google play services storage & cache
- Sync thread network via companion app -> troubleshooting -> sync thread credentials
- Check other ikea devices (i bought multiple) -> all fail.
- Checked if both the matter integration and otbr integration are successfully connected (they are)
To me it seems that mdns is broken, but I have no clue what changed in the meanwhile or how i can fix it (or even diagnose it!).
Any help is appreciated.
EDIT:
Solved! The main issue was that ip forwarding was not enabled. I had it, but apparently the settings do not persist after a reboot.
So in my case I had to re-run the step described here: Docker Install | OpenThread
So just to be clear: This was an otbr-in-docker issue. Hope it will help whoever reads this in the future.