Zigbee errors

Hi all,

I’m quite new to HA so I’ll apologise now for my lack of knowledge.

I’m running HA via VMWare on a Windows 10 PC, I have a flashed (tasmota) Sonoff ZB and ZHA integration installed. I don’t have many Zigbee devices (1 Samsung door contact, one Samotech door contact, 2 Innr Lights, 2 Samotech dimmers, 2 Xioami temp sensors, 1 Xiaomi door contact).

On a daily basis I am experiencing issues where all the devices go offline. The HA log shows:

2021-03-21 18:26:19 WARNING (MainThread) [bellows.zigbee.application] Watchdog heartbeat timeout:
2021-03-21 18:26:34 WARNING (MainThread) [bellows.zigbee.application] Watchdog heartbeat timeout:
2021-03-21 18:26:40 ERROR (MainThread) [bellows.ezsp] NCP entered failed state. Requesting APP controller restart

Rebooting the Sonoff ZB doesn’t help, a restart of HA seems to fix it.

Can anyone help?

Known issue with WiFi based bridges/gateways and why they are not recommended for production:


The same warning is also hidden here:


Options are to buy a USB-dongle/stick or Ethernet (wired) bridge/gateway or much more stable WiFi.

1 Like

Thanks for replying:)

It looks like a mixed set of feedback, some people saying it is the best thing, others saying it doesn’t work. I woke again this morning to find all my zigbee devices offline. a restart of the Sonoff ZB didn’t fix it, but a restart of HA did.

So what would you say is the best solution?

Is ZHA the issue? I could try Zigbee2MQTT instead?

I see there are several USB dongles out there, Conbee II, 2531? Again, some people have said they are rock-steady, other’s have “jumped ship”

What’s the best wired product/solution?

Root cause is your WiFi is not 100% stable or low-latency to use EZSP Zigbee-to-Serial bridge/gateway.

Zigbee2MQTT should be as unstable as ZHA if you use a EZSP Zigbee-to-Serial bridge/gateway with it.


  1. Buy USB-based Zigbee dongle/stick, ex.; Elelabs Zigbee USB Adapter or Electrolama’s ZZH

  2. Buy wired Ethernet bridge/gateway, ex.; Tube’s Zigbee Gateways / Tube’s ZB Store

  3. Invest in an 100% stable WiFi solution with 0% dropped packages and low-latency performance.

IMHO getting a new USB-stick Zigbee coordonator is the safe option today, and if you need it in a more flexble solution then you can always use it via ser2net or similar on a Raspberry Pi with wired Ethernet.

Note! Wired Ethernet based EZSP Zigbee-to-Serial bridge/gateway also require 100% stable network.

Which would you say is the best dongle?

Tube’s gateways are out of stock at the moment. I’ll email him and see when they will be back in and which is the “better” version.

I don’t know how I can improve the wi-fi, I have a Ubiquiti AC Pro AP about 15’-20’ away!

If you want to go straight USB, I’d recommend the ConbeeII. It’s a good, solid adapter that works well with ZHA, deconz, z2m, etc. However, if you want a LOT of devices (greater than 50), you’ll outgrow it quickly as it can only handle around 5 children and only a small amount of both normal routes and source routes.

I just got one of his coordinators recently and to be honest, it’s been REALLY good for my mesh. Personally, I like the CC2652p2 over the ESP version. I also have 2 of his routers. I know he is working his tail off right now to get more in stock. You can reach him here on the forum (@tube0013) and you can see my results here: https://community.home-assistant.io/t/zigbee-router-on-steroids

It’s not so much about the type of AP you have (I have the same), it is more about the channel interference between Zigbee and WiFi; They operate in the same 2.4ghz space and even the Unifi APs have issues with 2.4ghz interference.

Then it sounds like signal interference that might actually be your problem instead. Very possible that your Zigbee coordinator has reception problems because AP makes too much noice. Suggest moving your Zigbee coordinator further away from your WiFi access-points and other source of interferance.

Just code-in-progress hinted at, not only does both Zigbee and WiFi operate in the same freqency range but it is impoerant to understand that Zigbee radios transmits low-power signals and WiFi access-points has more powerful radios that transmits stronger signals.

I have submitted a PR with some related generic troubleshooting tips like that to the ZHA documentation that hope wiill get accepted, read → https://github.com/home-assistant/home-assistant.io/pull/18864

1 Like


My wi-fi and Zigbee channels are at the “opposite” ends of the 2.4 range. I have Zigbee on 15 (Wi-fi channel 3) and my AP is on wi-fi channel 13. Admittedly there is background noise from my neighbours’ APs that is the same frequency as the Zigbee, but I don’t have any choice about there, there is not a clean frequency range to use :frowning:
I’ve order one of Tube’s wired coordinators, so I’ll see if that solves the issue. But in the mean time I will move the Sonoff ZB bridge to a different location.

I’d check also at the transmit power on your AP as well. If it’s set to medium or greater, that would cause the Zigbee signal on the Sonoff to get drowned out by the AP.

Which one did you get?

I’ve just checked and transmit power is Auto.

I went for the EFR32 version as it has USB connectivity as well. It would have been great if it supported PoE, but alas not.

Appreciate any constructive feedback in home-assistant.io/issues/17170 if think Sonoff ZBBridge should be lísted in ZHA integration documentation as in top of the list of “known working radio modules” or not:

That way all those comments for and against can be collected in a single place for considerations.

I’ll have a look later when I’m sat in front of the computer.

It’s a difficult one… It might be caused by the sonoff zb bridge, but is resolved by restarting HA and not the bridge itself.

To me that points to two issues: Potentially an issue with the bridge causing the problem; An issue with HA/ZHA not correctly handling that issue.

While I wait for new hardware I’ve implemented an automation to detect when my zigbee devices become unavailable, this restarts HA.