Unstable Zigbee Network due to NWK address conflicts

Configuration Zigbee
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1

I have a large ZHA network where devices in different rooms intermittently become unavailable, reconnect by themselves, and sometimes cannot be controlled individually.

The important observation is that Zigbee group commands still work reliably. For example, two IKEA TRÅDFRI drivers forming one PAX light both respond to a Zigbee group command even when Home Assistant reports one of them as unavailable.

This suggests that multicast/group communication still works, while individually addressed unicast communication, address resolution, or routing is failing.

The logs also show persistent Zigbee short-address conflicts.

Home Assistant and coordinator hardware

  • Home Assistant Core: 2026.8.2
  • Home Assistant OS: 18.2
  • Supervisor: 2026.08.0
  • Installation: x86-64 Home Assistant OS VM on PROXMOX
  • Integration: ZHA
  • Coordinator: Home Assistant Connect ZBT-2
  • ZBT-2 firmware: 9.1.1.0 build 0 (20260818191539) (BETA)
  • Its a single family home with quite some distance to neighbors

I already upgraded from a SkyConnect to a ZBT-2. That didn’t really help so I updated the Firmware to the latest Beta.

Network size and device composition

The diagnostic contains 134 entries:

  • 1 coordinator

  • 88 Zigbee routers

  • 45 end devices

Manufacturer distribution:

  • 63 IKEA of Sweden devices

  • 15 eWeLink devices

  • 10 SONOFF devices

  • 8 devices without manufacturer information

  • 6 LUMI/Aqara devices

  • 5 Wing devices

  • Various additional Tuya devices

Radio channels

Current configuration:

  • Zigbee: channel 21

  • 2.4 GHz Wi-Fi: channel 1, fixed at 20 MHz

Unicast and routing errors

During approximately one hour in the newest log, the coordinator reports:

  • 313 × ZIGBEE_NO_APS_ACK

  • 197 × ZIGBEE_SEND_UNICAST_NO_ROUTE

  • 50 × ZIGBEE_SEND_UNICAST_ROUTE_DISCOVERY_UNDERWAY

  • 31 × MAC_NO_ACK_RECEIVED

  • Several delivery failures during the rejoin loops

Examples among the affected devices include:

  • 0x3BC0: 16 MAC no-ack failures

  • 0xBB31: 15 MAC no-ack failures

  • 0x8B5D: 10 no-APS-ack failures

  • 0x0307: 10 no-route failures plus repeated route discovery

  • 0xA27C, 0xA7E4, and 0xEDDC: additional no-route and route-discovery failures

The radio’s hourly counters also show:

  • 8,268 APS unicast packets received

  • 2,617 successful APS unicast transmissions

  • 605 failed APS unicast transmissions

  • 2,813 MAC unicast retries

  • 875 failed MAC unicast transmissions

  • 147 route discoveries

  • 150 neighbors added

  • 150 neighbors removed

  • 84 neighbors marked stale

  • 11,537 network decryption failures

Until a few weeks ago everything worked perfectly for over a year. But for the last couple of weeks the entire network is just unstable and is driving me insane. I tried to analyze the large log files with ChatGPT and Claude but they only tell me that there an issues but not how to solve them. I looked through Reddit and this community but I haven’t found anything close to my issues.

2

I’m also having an issue with Ikea devices suddenly starting to drop off the mesh - they have been solid for years and now simply go offline and I have to toggle the power to get them back online. All I’ve done recently is upgrade Z2M to the latest version - this behaviour started around that time.

3
4

I followed everything in the guide or other general guidelines regarding Zigbee and interference.

5

Tracked mine down to a failing router device (Ikea switch). Maybe you have a similar issue?

6

@Neil_Brownlee how did you identify the failing device? I’m interested to know as I also have a large network and want to work out what is the root cause of drop offs

7

The relay was clicking. The Zigbee map showed my routers that were connected to it were the ones that kept dropping. It’s not easy to locate a bad router - but the map is your friend.

9

So i reset my entire Zigbee network. Turns out a few devices have been causing the issues, all Ikea devices. New issues is that some New IKEA Kajplats won’t pair and stay connected.

10

Interesting as one of my IKEA bulbs lost connection recently so I decided to simply remove it from ZHA and didn’t bother to pair it again. The network seemed to stabilise a little afterwards. And just now another IKEA bulb went offline.
Quite possibly coincidence in my case as it seems any ZigBee device can drop off my network including dedicated routers, Hue bulbs and cheap AliExpress Tuya and ewelink stuff.

11

My failed switch was Ikea too …