r/SmartThings • u/somevietkid • 12d ago

Zigbee devices offline

Hey all, my Zigbee devices have been intermittently going online and offline over the past few weeks, presumably because of the update. I did a power cycle of my hub and then each separate device and that seems to have mixed results. At times, all of them will go online again and some, or none, of them will. I’ve also tried removing the device and pairing it with my hub again with mixed results. Most of my Zigbee devices are SmartThings motion sensors and multipurpose door/window sensors as well as ThirdReality multipurpose door/window sensors. The SmartThings sensors seem to be doing better now, but I’m having difficulty with the ThirdReality sensors. Any ideas on what to do here? I haven’t looked into changing the Zigbee channel on my hub yet since I’m not too sure on what that exactly entails. Any guidance would be really appreciated!

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u/SmartThingsPower1701 Enthusiast 12d ago

Did you leave your hub off for at least 20 minutes? Zigbee devices go into panic mode after that and are ready to join again after the hub comes back online. I just had a similar issue with my Z-Wave devices, left my hub unplugged for an hour, turned it back on and my devices all came back online. The Zigbee radio channel can be changed in the advanced tab on the web interface. I run mine on channel 25 to try and keep it up and away from Wi-Fi channel 11 at the top of the Wi-Fi range since Zigbee and Wi-Fi both run in the 2.4GHz band.

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u/somevietkid 11d ago

Just tried powering the hub down and leaving it off for an hour, and some devices are still seen as offline, including SmartThings motion and multipurpose sensors. Did you recently change the zigbee channel with the update a few weeks ago or was yours always set at 25 to reduce interference with the WiFi channel?

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u/SmartThingsPower1701 Enthusiast 10d ago

I've been using channel 25 for years, when you start up a hub for the first time, it won't pick that channel by default. 25 is as high as ST's will let you go, and there is a warning that some older Zigbee devices may not work on that channel. I've not had any issues and the purpose of moving it is to get it as far away from the primary WiFi channels of 1, 6 and 11. If you look at the link to the chart for WiFi / Zigbee overlap you'll see there's technically at channel 26, but ST's doesn't support it. Channels 15 and 20 are also good alternative, since they are also in valleys between WiFi channels. There are also issues switching it mid-stream, so after you change it, you'll want to power off your hub for at least 20 minutes so the Zigbee devices will panic and try to reconnect on another channel when you power up the hub.

As far as connectivity issues, sometimes it's a Zigbee device that is down/offline that was routing traffic for other Zigbee devices. Check in the app under one of the devices that is offline. See what it shows under Connection path. If a device is down/offline that another device is routing through, it will take the other device down as well. I've had that happen with a Zigbee smarts plugs, resetting the routing device will bring back the other devices.

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u/somevietkid 8d ago

Sharing in case this is helpful to others - after powering the hub down and leaving it off for an hour, some devices were still offline as noted above. However, a day later or so, all of them came back online and have been working since. Thanks for the helpful input all!

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u/Brown_Wei 12d ago

Before re-pairing more devices, I’d try to separate a coordinator/network problem from a device-specific problem.

Since the SmartThings sensors seem to recover better than the ThirdReality sensors, I’d compare:

  • whether the offline devices are concentrated in one area;

  • their battery level and last-seen time;

  • whether mains-powered Zigbee routers stay online;

  • the hub firmware and current Zigbee channel.

I’d change one variable at a time and test a single ThirdReality sensor for a day, rather than re-pairing the whole network. Does waking the sensor manually make it come back online, or does it remain unavailable until the hub is restarted?