Hello, I have a problem with pairing HA with Matter Thread ALPSTUGA IKEA. I have an SLZB-MR5U coordinator connected to LAN PoE (SLZB OS v3.3.3.dev1 software and with 2 radios where 1 is a zigbee coordinator on channel 25, and the 2nd radio Thread currently on channel 15. I have installed in home assistant (HA OS 2026.7.1 supervisor 202.06.2 operation system 18.1) with IPv4 and IPv6 enabled, Matter (Current version: 9.0.4), Thread and the current official application with HA Traead border router and correctly launched border router and with correctly loaded credentials on the border router on Samsung A35 5G with WiFi of the same network as the connected SLZB-MR5U and Bluetooth enabled as well as location. Home assistant is a virtual server on proxmox, in which both: cat /sys/class/net/vmbr0/bridge/multicast_snooping and cat /sys/class/net/vmbr0/bridge/multicast_querier both give “1”. Proxmox, Home Assistant, and the Thread and Matter add-ons were restarted, as was Samsung. Regardless of the Thread channel (unsuccessful attempt on channel 15), when trying to add the IKEA AlpStug to Matter by scanning the device’s QR code via Samsung, after about 60 seconds of connection, it says: “Checking the Thread network connection..383’ and Matter animation.” Then, a prompt appears: “Unable to connect to the device, check if the phone is connected to WiFi.” I can’t add the device. The attempt also failed on a brand new phone and on the second AlpStug.
HA OS 18.12HA
Core 2026.7.43
Matter Server 9.1.04
OTBR 3.0.25
SLZB-MR5U6
ALPSTUGA (2 units tested).
The phone stops at:
“Checking the connection to the Thread network”
but:
Matter Server never logs:
commission_with_code
Discovery
Establish PASE
and OTBR doesn’t see the new device attached.
BorderRouterRegistry BR instance dropped
source=meshcop
xa=missing