After changing zigbee channels, all of my devices (20) are no longer able to connect to the hub. I did a shutdown/power-off/wait 30 mins in order to enter panic mode. It's been 2+ hours since, no devices showing up. I tried to enter pairing mode and re-pair devices. Nothing... I toggle radio on/off, nope.
Prior, the zigbee has been pretty reliant, but lately, I have a hue motion sensor that keeps falling off, this is why I tried a channel change. But now nothing will pair. The hub load seems to be in normal range.
Anyone with a starting idea, other than RESET forcing me to try to add each device again, please comment.
Try a restore before you made the change of the zigbee channel? I don't know if that is part of the backup or not. Or try setting it back to the original channel first?
Thanks for the replies. I have set back to original zigbee channel. With my mesh wifi system, I have found channel 18 the be the most isolated. I understand that ch 20/22 are recommended by most and when I had the one device acting up, this is what I changed to. It's been over 10 hours now and only one zigbee light is working. I've had this hub C7 for years now and never had any problem where either of the radios stopped working all out.
It doesn't seem to be common knowledge but Zigbee HA 1.2 spec includes a 'preferred channel mask'which specifies the channels that a coordinator using the Home Automation profile should choose from when auto selecting a channel upon PAN ID formation; this includes performing an energy scan of each of those channels (looking for the quietest one at the time of the scan). In an ideal case it would result in choosing the channel which not only has the least overlap with the most commonly used 2.4Ghz wifi channels, but the least busy one of the lot.
This standard mask includes Zigbee channels 11, 14, 15, 19, 20, 24, and 25. It doesn't mean other channels won't work (or actually be preferable in a given environment, since the energy scan is only performed when the PAN is set up for the first time). But those are the channels that devices using the HA 1.2 profile will check first when put into 'join' mode and start looking for a network to join.
Not knowing any of this when I set up my C-3 years ago, I changed the default channel to 18 (I forget what the C-3 had initially chosen, but it was one that appeared to overlap with a neighbor's 2.4Ghz Wifi). It's worked out fine, with one exception: I've run into a couple of devices (the most mainstream being a 2019-vintage GE/Jasco Zigbee dimmer plug) that cannot initially pair on channel 18.
After finding that the plug did join successfully to my ST hub (running on channel 11) I found that I could join it to the C-3 by temporarily changing the C-3's channel (from 18 to one of those in the preferred channel mask), joining the device, then changing the C-3's channel back to 18-- the problematic device had no issues automatically following the C-3's channel change to 18 once being joined on a preferred channel; its radio works fine on 18 but it's just not programmed to scan that channel on initial join after reset.
This may be the case. I set the hub into safe mode which assigned ch 11 to zigbee radio. Nothing paired, but then I power cycled the hub, it went back to 18, but then pairing began to succeed again. I am not sure why ch 18 is in the sweet spot in my house with 4 mesh AP's (Deco M5). But, it still continues to provide the least amount of overlap.
