C8 dropping zigbee and wifi connections

I bought 2 C8 hubs to replace my older C7/C5 setup. Following are the details of the setup

  • 1 C8 running zwave network
  • 1 C8 running zigbee network
  • Both the hubs are sitting next to each other
  • Both are connected over wifi
  • Unifi APs all over the house, restricting to wifi channels 1 and 6 only. Neighbour's house is quite some distance away so almost zero interference
  • Zigbee running on channel 26 and power 20


  • Either due to the external antenna or due to more centralized location (thanks to wifi), my networks are far more responsive than my earlier setup
  • The C8 running zwave has been pretty trouble free
  • However the second C8, one running the zigbee network, has been very problematic off late and dropping connections for extended periods with both the wifi and zigbee radio
  • I have also caught the faulty (zigbee) hub blinking blue and green lights alternatively a couple of times which got fixed with a reboot

Attaching couple of screenshots from the Hub logs

26 is not a good choice for a couple of reasons. Only newer devices support it and it has a government mandated lower power output allowance for that channel. 15, 20, and 25 are your best bet.

Is also start at 16 default for power at first.

Set your zigbee for channel 20 with 8 for power, make sure your wifi is set for 6 or below and see how things behave... Also how close is your c8's to your router?

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That's where I'm at too. My unifi is on 1 and 6 for the 2.4 band. I also have the 2.4 power backed off to push clients to the 5ghz band.

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I would make separate SSID's for the 2.4 and 5ghz bands just to keep it seperate and eliminate other issues with iot devices that don't like combined SSID's...

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Band steering and lower 2.4 power has been working pretty good for me. (Knock on wood).

But I'm OCD and have 3 SSIDs as it is. Private wifi, guest wifi, and a third for stuff like cameras and lesser trusted stuff like devices with sketchy firmware. The last one blocks phoning home unless I permit it.

Then I'd have 6 if I separated :grinning:

A lot of iot crap has problems with the mix. I find it easier just to keep them seperate. (I have 5 myself, only guest is mixed though)

Make a VLAN Network and WIFI using only 2.4 and assign all your IoT devices to it, it is pretty easy to do on the UDMs

I have 2.4 and 5 on separate SSIDs and the C8s connect to the 2.4 one. I don't have any issues with wifi coverage anywhere in the house and with the gazillion other devices I have except for the C8 running zigbee network. I don't have any strong evidence to suggest that the zigbee power or the channel is the issue here. The main problem is that the device is losing connection to the wifi AP.

It'd be helpful if there's a way for me or any support person to first look at any (more detailed) diagnostic messages on the hub and start debugging from there.

I'm running a guest wifi SSID specifically for the backbone for Smart devices. If it's IOT it's on that SSID. 6 different SSID's configured for my network devices.

Dropping the zigbee power to 12 from 20 seems to have fixed all issues