Setting up the first Matter device with an Android phone fails

Hello everyone,
after setting up an OTBR & Matter in Home Assistant, I cannot add a device.
My infrastructure:

  • Home Assistant as a VM under Proxmox
  • VM external with IP 192.168.20.151
  • SMLIGHT - SLZB-07 passed through as a USB device and is recognized
    (/dev/serial/by-id/usb-SMLIGHT_SMLIGHT_SLZB-07_…)
  • Android phone with IP 192.168.130.47
  • Networks are routed via an OpenWRT router (192.168.1.1)
    What I’ve done:
    Hardware:
  • SMLIGHT - SLZB-07 USB stick (with Matter firmware)
  • Installed OTBR under Add-ons
  • Added Thread under System Devices & Services
  • Enabled Preferred Network (ha-thread-fd7c) under the gear icon
  • Used login credentials for Android & iOS
  • On the Android phone, in the Home Assistant app under Companion App Troubleshooting,
    Synchronizing Thread Access Data
  • Aqara FP300 cannot be added via Matter (See attachments)

What else can I check or change? I would appreciate your support.
Attachments:

Could problems arise if the Home Assistant OS is on a different network than the Wi-Fi devices?

Regards, Stefan Harbich

Yes

Phone should be on network devices will use
HA should be on same network
IPv6 enabled on network
Matter server on same network