I have about 50 Zigbee devices… today, 8 semeed unavailable (all battery-powered) were no longer responding. Pressing the pairing button seemed to work fine. I replaced the battery (which is good quality), but they still don’t respond.
I restarted HA… I removed and inserted the Cobee II a couple of times.
Only by removing them from ZHA and starting the pairing procedure did they work again.
Half of the devices are far away but the other four are a few meters from the coordinator.
The thing is, I also have other devices that have had no problems (some battery operated, some powered).
The last thing that was done was to add an Ikea Matter over Thread device this afternoon. But I don’t know if that caused the problem. I don’t remember having problems immediately after adding it, but hours later. If any neighbors changed something, I have no idea.
Thread uses same frequence as WIFI, So now you have wifi, zigbee And thread fighting for the same “space” , check which channels they are using, and possible interference issues