Unable to pair Matter-over-Thread device (Heiman HS-7255E5-M) with Home Assistant (ZBT-2) – wrong Thread network / no Border Router detected

Configuration Matter/Thread
1

Hi everyone,

I’m currently trying to add a Matter-over-Thread device (Heiman HS-7255E5-M CO detector ) to Home Assistant, but I’m stuck despite having a seemingly fully working setup.

I’m hoping for some guidance, as I’ve already gone through most common troubleshooting steps.

:wrench: Setup

  • Home Assistant (latest version)
  • Intel NUC (running in Proxmox VM)
  • Home Assistant Connect ZBT-2
    • successfully configured as Thread Border Router
  • Add-ons:
    • OpenThread Border Router → running stable
    • Matter integration → active

:white_check_mark: What works

  • Thread integration shows:
    • my own network (ha-thread-xxxx )
    • Border Router active
  • Network is set as preferred
  • Matter integration is active and reachable
  • ZBT-2 has been correctly flashed to Thread firmware
  • USB passthrough in Proxmox is working

:cross_mark: Problem

When trying to add the device via the Home Assistant app:

Behavior 1:

  • Error message:

“Thread Border Router required”

Behavior 2 (different phone / previous device):

  • Device is always assigned to the wrong Thread network:
    • NEST-PAN-xxxx (Google Nest Thread network)

Behavior 3:

  • Taking over the device from Google Home fails:
    • Error code 1

:test_tube: Troubleshooting steps already attempted

Thread / Home Assistant

  • Thread network:
    • present and working
    • set as preferred
  • Matter integration:
    • removed and reinstalled
  • Home Assistant:
    • restarted multiple times
  • OpenThread Border Router:
    • restarted
    • data cleared and reconfigured

Device (Heiman HS-7255E5-M)

  • multiple factory resets:
    • battery removed
    • button held while reinserting battery
    • held for 20+ seconds
  • pairing attempted immediately after reset

Google / Nest influence

  • Google Home app uninstalled
  • Nest Hubs powered off / unplugged
  • still:
    • NEST-PAN network remains visible / used

Android / Smartphone

  • tried a second device
  • reset Wi-Fi + Bluetooth
  • rebooted device
  • cleared Google Play Services data

→ still:

  • wrong network selected
  • or “no Border Router found”

Thread credentials

  • option “Use for Android & iOS credentials” is present but:
    • greyed out (not selectable)

:thinking: Current assumption

I suspect a conflict between:

  • Google Thread fabric
  • Home Assistant Thread fabric

Possibly:

  • Android Matter stack is caching or prioritizing the wrong network
  • Matter integration in Home Assistant is not correctly acting as commissioner

:red_question_mark: Questions

  1. How can I ensure that only the HA Thread network is used ?
  2. How can I completely remove a “stuck” Thread network like NEST-PAN ?
2

u are not alone my friend, i do have the same Problem, when i try to connect the matter device the wrong networe shows up

3

Solution:

Make sure to clear out both cache and data storage.

If the entry has a “key in a phone” icon, then that is good (and this is why it is grayed out)

I didn’t see mentioned where you did a “sync” of the Thread credentials to your Android HA Companion App. Make sure you do this (after clearing out Google Play Services)