Matter over thread (Solution)

Questions & Help
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Problem: IKEA Matter-over-Thread devices (BILRESA button, ALPSTUGA air quality sensor, MYGGSPRAY motion sensor) stayed stuck on “Unavailable” on Homey Pro, or dropped offline again within minutes of a successful pairing.

Setup: Homey Pro + ISP modem (Ziggo/cable, NL) + Google Wifi mesh (note: the original 2016 Google Wifi, with 3 identical pucks, has zero Thread support itself so it wasn’t secretly adding extra Thread routers to the mix).

What turned out to be the actual cause not a lack of Thread mesh, but two network issues:

  1. Double NAT between modem and wifi mesh. Turning off wifi on your ISP modem is NOT the same as enabling “bridge mode” without bridge mode, the modem keeps routing/NAT’ing on its own, creating a double-NAT layer with the mesh router sitting behind it. Enable bridge mode through your ISP’s app/portal (for Ziggo: Vodafone & Ziggo app → Service → Internet → Bridge Mode). Note: the cable needs to be in LAN port 1 (or the 2.5Gbps port) for bridge mode to work, otherwise you lose internet entirely. To confirm it worked: your mesh router’s WAN address should show a genuine public IP, not something in the 192.168.x.x or 10.x.x.x range.

  2. Homey Pro was connected via both wifi AND ethernet at the same time this turned out to be the bigger culprit. Check this in Homey’s system info screen in the app: if both Wi-Fi and Ethernet show “Connected: Yes”, you have this issue. Two active interfaces on the same network can disrupt mDNS/multicast traffic, which is exactly what Matter/Thread commissioning relies on to discover devices locally. This is a known, recurring Homey Pro issue reported by others too.

Fix for #2 (disabling wifi on Homey Pro isn’t exposed in the normal app settings):

  • Go to tools.developer.homey.app/tools/api-playground, log in with your Athom account, select your Homey
  • Run: Homey.system.disableWifi();
  • Confirm via the system info screen that Wi-Fi now shows “Connected: No” while Ethernet still shows “Yes”

Result: after these two fixes, all three devices paired reliably right away some even reconnected automatically without needing to re-pair at all.

Bonus tip: once a mains-powered Matter-over-Thread device (like ALPSTUGA) is stably connected, it likely acts as an extra Thread router in your mesh itself. So check whether your existing mains-powered devices are already extending your coverage before buying a dedicated Thread router (like IKEA’s TOFSMYGGA) only worth it once a device genuinely needs to sit far from Homey Pro.