Hey all,
Never written here on the forum, so no idea how this forum works or how friendly it is. I hope for the best.
I’ve run a Home Assistant server, inside a Proxmox VM since January, it has worked relatively well and in February I integrated a ZBT-2 and ran it with Thread firmware to connect IKEA Matter devices, it was a pure 4-day pain to get it working, but finally got it working.
The network still works, I can control lights and sockets, I can get presses from buttons and so on.
But today, I thought I would integrate my Samsung Smart TV, so I tried that and read that I should enable IGMP snooping and IGMP proxy, still couldn’t get that to work probably because I have the TV and Home Assistant VM on different VLANs. So I closed that project and thought that’s no problem, I can continue my life without it.
About an hour later I thought I would add some IKEA Myggspray (motion sensors) to the system and I get that I need to add a Thread Border Router to my system - message from Home Assistant Android app. This shouldn’t happen as it has worked perfectly before, I have 46 IKEA Matter devices connected to my Home Assistant system.
So I found that ok, IGMP snooping and IGMP proxy can f’ up Thread networks, so I disabled that. I have restarted the router, Home Assistant services (matter, thread, OTBR) and the Home Assistant server itself. I have restarted my phone. Still doesn’t work.
Instead I get “Matter is not available right now” after clicking “No the device is new” when trying to add a new device in the Android app.
With both errors in the app, the Thread network was no longer visible in my phone under Settings → Google → All services → Thread-networks. It has been visible there before and I could see all my IKEA devices there. It doesn’t matter that much to me, but when everything worked, that was what I could see.
I downloaded a Bonjour/mDNS service browser on my phone, it couldn’t see my Thread Border Router at first, but after I did the restart of Home Assistant VM it popped up in the app - see attached image of the service browser app. The app can see Home Assistant, Thread Border Router, my phone and some other devices available via mDNS discovery.
At one point the Thread network was visible during all this troubleshooting, but then disappeared under “Settings → Google → All services → Thread-networks”, from not visible to visible shortly and then not visible again.
Phone via WiFi is on the same network as the Home Assistant VM as well as of course the ZBT-2 configured as Thread Border Router.
Both phone and Home Assistant has IPv6 addresses configured via IPv6 service on the network.
mDNS is of course active both globally and for the WiFi network specifically.
Nothing hardware wise has changed, the ZBT-2 still uses the USB cable that came with the device and is as far away from the server itself physically as possible (haven’t been moved since it worked), no USB port has been changed.
The Matter/Thread network otherwise works more or less “perfectly”, I can control lights, sockets and so on as I said.
The router I use is an Ubiquiti Dream Machine SE which itself has no IPv6 DHCP services, so instead I have a VM giving out IPv6 addresses on the specific VLAN (100) - again, since the beginning in February, this has worked perfectly. That service is also running, so no problem there as far as I can tell.
Attached you will find two logs, one for “core_openthread_border_router” and one for “core_matter_server”.
OpenThread Border Router - version: 2.16.5
Matter Server - version: 8.3.0
Home Assistant OS - Core version 2026.4.1 (same “problems” with 2026.4.0)
Home Assistant OS - Supervisor version 2026.03.2
Home Assistant OS - Operating System version 17.1
Home Assistant OS - User interface 20260325.6
Another thing that I think is strange that if I unplug ZBT-2 from the computer/server… it always starts up in Zigbee mode (led starts flashing again), so I have to flash it via Home Assistant again to Thread mode. The Thread networks starts up fine after that, but kind of strange?
Edit…
Apparently I can’t add files to the post…
https://chrisf.se/ha/core_matter_server_logs.txt
https://chrisf.se/ha/core_matter_server_logs2.txt
https://chrisf.se/ha/core_openthread_border_router_2026-04-04T12-11-42.297Z.txt
https://chrisf.se/ha/core_openthread_border_router_logs.txt
https://chrisf.se/ha/matter_log1.txt
https://chrisf.se/ha/otbr_log1.txt
