Hi everyone 
I’m currently experimenting with Matter and Thread, which I believe will play a big role in the future of smart home tech. Matter over WiFi works fine in my setup, but Matter over Thread is giving me trouble.
My Setup
• Home Assistant OS on Raspberry Pi 5
○ HA OS: 16.2 (aarch64 / raspberrypi5-64)
○ HA Core: 2025.10.3
○ HA Supervisor: 2025.10.0
• Zigbee2MQTT with Sonoff Zigbee 3.0 USB Dongle Plus — works flawlessly
• ZBT-1 stick flashed as Open Thread Border Router, following HA standard instructions
• Matter Add-On installed
• Open Thread Border Router Add-On installed
• Matter over WiFi works — 2 nodes active
Problem: Matter over Thread fails
Trying to commission a Third Reality Smart Color Night Light via Thread fails in HA. The device connects fine via its own app and Apple Home, so Thread support seems OK.
Matter Add-On log:
INFO [matter_server.server.device_controller] Starting Matter commissioning with code using Node ID 47. CHIP_ERROR [chip.native.CTL] Discovery timed out CHIP_ERROR [chip.native.ZCL] Secure Pairing Failed WARNING [chip.ChipDeviceCtrl] Failed to establish secure session to device: CHIP Error 0x00000003: Incorrect state ERROR [matter_server.server.client_handler] Commission with code failed for node 47.
Open Thread Border Router Add-On log:
[W] DuaManager: Failed to perform next registration: NotFound mDNSPlatformSendUDP got error 99 (Cannot assign requested address) sending packet to ff02::fb on interface fe80::d0fe:9bff:febf:4990/veth965c185/16
What I’ve tried
• Verified ZBT-1 is flashed and recognized as OTBR
• Matter over WiFi works fine
• Device works with Apple Home and its own app
• AI suggests it might be mDNS-related, but I don’t fully understand that part
Has anyone successfully commissioned Matter over Thread with a ZBT-1 stick on HA OS?
Any ideas, tips, or troubleshooting steps would be greatly appreciated!
Thanks in advance 