Any way to recover 12 Zigbee lights that have gone offline?

I have 24 lights outside around the house and half of them suddenly went offline. I can’t be sure what caused this as I was doing a few things including troubleshooting another separate issue and installing a new Wi-Fi mesh network at the time.

I have cut power to the lights at the breakers for 30 seconds, 3 times. And rebooted ST twice. They never reappear as online in ST.

Any help appreciated. I really don’t want to delete and re-pair them as they’re tied to a bunch of routines in both ST and Google Home. Thanks in advance.

one thought could be channel interference caused by your new wifi mesh network. login to Advanced Web App, go to the hub section and tap on your hub name. check to see what channel is being used by your zigbee network and compare that to the channel being used by the 2.4 ghz part of your wifi network. If they are overlapping, you may need to adjust one or both.

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Yeah, ST Zigbee is using Channel 25 and the Wi-Fi 2.4GHz is using 3 and 5GHz (which I don’t think affects Zigbee) is 48. Would that be a problem?

Though I would expect the lights to go on and offline if it were interference, but they’ve been solidly offline for 3 days.

Bump. Anyone?

Turn your hub off for 30 minutes and on again. Everything zigbee should go into panic mode and rejoin. If not try re-adding devices, they may be recognised as already having been connected before in which case your routines may still work.


Looks like your channels are OK, but strong Wi-Fi can block out Zigbee, which is a much weaker transmission on the same frequency. This is a common issue, and is probably historically the reason why zwave was more popular for smart light switches (Wi-Fi doesn’t interfere with zwave.)

I have previously written about an issue I had at my own house, where if I put a Wi-Fi booster on the north wall of a room all the Zigbee devices to the west of it fell off-line. But if I just plugged it in on the east wall instead, everything operated fine.

So, in this specific case, my guess is that you improved your Wi-Fi to the point where your Zigbee messages couldn’t get through. It’s always a balancing act. :thinking:

As a former field tech, there are three typical approaches to fixing this issue.

  1. move the Wi-Fi equipment. As I mentioned, This worked for me, but my issue was with a single Wi-Fi booster device.

  2. move the Zigbee equipment. Easier to do with, say, batterypowered sensors than lightbulbs and light switches, obviously.

  3. add more Zigbee repeaters. Inexpensive smart plugs like the IKEA tradfri ones are a good choice for this. The Zigbee profile that smartthings uses can handle up to 15 hops from the end device into the hub. So you can use a repeater in every room, or even a couple, and improve the mesh strength that way just because the signal doesn’t have to travel as far each time. This is the same thing we do to set up networks in adobe or cement homes where you can’t get signal through the walls and you have to bounce it through the doorways and then down the hall.

Once you’ve physically put the new repeaters in place, do the Zigbee heal process that @Andrew_Bartlett mentioned:

Take the hub off power (including removing any batteries)
Leave all the other Zigbee devices on power
Wait 20 to 30 minutes
Put the hub back on power

This will cause all of the Neighbor tables to be rebuilt, but the process can take a few hours, so you may not see results until the next day.

Smartthings doesn’t really give us the diagnostic tools You would need to find a specific weak places in the mesh so it can take a lot of trial and error. Just remember that any place where your Wi-Fi signal is really strong is a place where your Zigbee messages will struggle to get through. :disappointed_relieved:


Wow! Keep learning and learning. Thx

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Forgot to mention, since you got a new Wi-Fi mesh router, best practices would say to make sure the smartthings hub is at least 3 m away from the Wi-Fi router. I know a lot of people will say that they have their Wi-Fi router right next to the SmartThings Hub and everything runs fine, and I’m happy for them, I’m just telling you best practices since you are having some problems.

If you are interested in reading more about these issues, start with post 11 in the following thread (i’ll link directly to that one), read it, then go back up to the top and read the whole thing. :sunglasses:

A Guide to Wireless Range & Repeaters - #11 by JDRoberts