I’m having issues with Matter over Thread in my Home Assistant setup. I’ve been trying for weeks now reading on forums and debugging my setup. But nothing works…
I started with a Sonoff ZBDongle-E (the right version for Thread) but could not get it to add new devices. Figured I got the wrong version after a lot of discussion with Chat GPT. So I gave up and ordered the ZBT-2 thinking that there was no chance it would not work.
To start with I had issues installing the Thread firmware through the companion app. Solved that and all add-ons and integrations installed fine. Everything looks fine but I have some troubles to sync credentials. I start in settings for the companion app > Troubleshooting > Thread and sync credentials. Then I go to Integrations > Thread and send credentials to Home Assistant and then to my phone (IOS). Sometimes it works, but most of the time I get “Thread network credentials does not match with any of the active thread networks around”.
When the credential sync works, I can start the process to add a new device through the matter integration. Sometimes it says connecting and then configuring but then it says that the device cannot be added. Most of the time it stays on connecting. I’ve only tried with IKEA myggbett since that’s the only Matter over Thread device i got so far.
I have tried to remove everything and then add again, manually reinstalling firmware, tried different USB outlets, countless different settings. I have read ALL issues posted online. What am I doing wrong?
My setup: HAOS 2026.2.2 on a TrueNAS server. iPhone running IOS 26.2.1
I get some concerning logs in OTBR:
00:00:37.426 [W] DuaManager----: Failed to perform next registration: NotFound
The root cause of the problem was that the host (TrueNAS Scale) did not pass through IPv6-traffic/messages correctly from the VM (HAOS) to the rest of the network. Though my understanding of IPv6 is limited.
I figured this out, with help from ChatGPT, when I could only see the service _meshcop._udp. sporadically on my iPhone. The solution was to add a dedicated NIC and pass it through to Home Assistant OS (not NIC passthrough, PCI passthrough). Previously the host and VM shared one network interface.
Then i had to reset the border router in the Thread integration to get a new network name and PAN-ID to get it to work.
I hope this can be of help to others experiencing similar issues.
I am experiencing exactly the same issue described in this thread with a ZBT-2 used as an OpenThread Border Router in Home Assistant.
My setup is the following: Home Assistant OS with both OTBR and Matter Server integrations installed. The ZBT-2 is correctly detected, and the Thread network appears to be created and visible. On iOS, the Thread credentials sometimes sync correctly via the Apple Home app, but this behavior is very inconsistent.
The main issue is that Matter over Thread commissioning fails randomly. In some cases, the pairing process starts correctly but then gets stuck during the connection or configuration phase and eventually fails with “unable to add accessory.” In other cases, Apple Home seems to take over the commissioning flow even when I initiate it from Home Assistant, which makes the process even more inconsistent.
I have already tried several troubleshooting steps: fully resetting and recreating the Thread network in Home Assistant, resetting the ZBT-2, reinstalling OTBR and Matter Server integrations, removing Thread networks from iOS/iCloud Keychain, and performing multiple full restarts of Home Assistant, the network, and the iPhone. Despite all of this, the behavior remains the same.
I also noticed that some users seem to work around the issue by clearing old Thread credentials from iCloud Keychain, recreating the Thread dataset entirely, using a different phone for commissioning, or adjusting IPv6/network exposure on the host running Home Assistant.
Has anyone here identified the exact root cause or found a stable fix? Most importantly, how did you resolve it in your case?
Any concrete feedback would be highly appreciated, as everything appears to be correctly configured on my side, but commissioning remains unreliable or impossible.
I just tried it, but it doesn’t seem to solve my problem. I can’t figure out what’s causing it. I read the forum post you pinned, but unfortunately, it didn’t help. I sometimes get the message “Unable to add accessory - Pairing Failed” or “Unable to add accessory - Home could not connect to this accessory.” I don’t know what information you need to help me.
Last night, I did what you told me a second time, then I fully restarted everything (devices and Home Assistant). This morning, Matter is finally working! Thank you very much !
Can somebody pleas helping, i was having the same issue adding new devices. i bought a NIC and trying to install ist. But now HA crashes after launching(NIC+Passtrough).
If only use the passtrough device, the HA crashes
im not an expert at all, just really tired it dosnt work.
