Why do certain lights go unavailable when other lights and switches/sensors are fine?

OK so the title needs more context. I have a few devices which are notorious for going offline, seemingly randomly.

In the kids bedroom we have a pendant light (branded innr) which is stable whilst a Hue Bloom in the same room, feet from the pendant light, goes offline regularly and seemingly randomly.

In the bathoom I have 5 GU10 bulbs in a group and one or more bulbs randomly go unavailable and then will reappear when they feel like it.

On the same floor we also have a landing with a Ikea Tradri bulb and in the master bedroom another Innr branded bulb - so I don’t think the issue is coverage - all rooms have other Zigbee devices in them (i.e. the kids bedroom has a zigbee battery powered switch and the bathroom has multiple devices, switches, sensors etc.) further adding to the conclusion range/coverage isn’t a problem.

I’m running the latest version of HA and “rocking” a SkyConnect stick (which I think is the root of the issue as frankly it’s been rubbish since I migrated my network from z2m with a Sonoff ZB stick to ZHA and SkyConnect).

Just wondered if there’s anything I can do other than ditching the SkyConnect and/or ZHA altogether and returning to z2m.

My bathroom dashboard - all devices are Zigbee, one bulb doesn’t want to play…

Similar story in the kids bedroom…

Interference, as well Zigbee channel choice, can still be a problem, but you also need to understand that Zigbee compatibility between different manufacturers/brands is not always that great which is why I personally recommend getting a few dedicated “know good” Zigbee Router devices. Read and follow:

https://community.home-assistant.io/t/guide-for-zigbee-interference-avoidance-and-network-range-coverage-optimization/515752

A tip is to buy a few known good dedicated Zigbee Router products and place them strategically as Zigbee repeaters. Personally, I suggest buying and adding at least three such devices to your network.

For example, the “IKEA Tradfri Signal Repeater” works very well out-of-the-box, while a more powerful alternative is to make yourself some semi-DIY variant by flashing the correct Zigbee Router firmware to Zigbee Coordinator USB dongles and then using them as stand-alone Zigbee Signal Repeater devices in USB-chargers for power, like for example the Sonoff ZBDongle-E (EFR32MG21 based) or the Sonoff ZBDongle-P (CC2652P) work great as dedicated stand-alone Zigbee Signal Repeaters with recommended firmware.

Here are also some ZHA integration documentation sections directly and indirectly related to this topic:

https://www.home-assistant.io/integrations/zha#best-practices-to-avoid-pairingconnection-difficulties

https://www.home-assistant.io/integrations/zha#zigbee-interference-avoidance-and-network-rangecoverage-optimization

https://www.home-assistant.io/integrations/zha#defining-zigbee-channel-to-use

https://www.home-assistant.io/integrations/zha#knowing-which-devices-are-supported

https://www.home-assistant.io/integrations/zha#zha-exception-and-deviation-handling

I can only tell you that I see this periodically in my system and it is not a coverage issue as I one bulb out of 7 on the same track will disappear. My experience is that some bulbs are just not super-reliably. I have about 70 IKEA bulbs and every two or three months 2-3 of them lose their ability to find the network. Re-adding them fixes it, though.

Went into the bathroom today to find the bulb which was not working last night is now happily playing whilst another in the same room isn’t - it’s really frustrating.

I get the argument that different brands may not play well together, but this doesn’t ring true to me when we’re talking about a cluster of 5 bulbs from the same manufacturer (Ikea) when 3 are rock solid and 2 take turns in annoying me :smiley:

Sorry I should have said “thanks” for the links - I’ll take a look as it’s bugging me how unstable it seems to be.

Regarding channel - mine is at the default 15 but I have 3 WiFi APs around my house which my UniFi router auto assigns channels to an invariably they are overlapping - but again given the issue is isolated to a small number of bulbs which are all in proximity of other bulbs which are unaffected I’m sceptical if it’s interference but happy to try mitigating it.

You can set a static WiFi channel on each Unifi ap → ZigBee and Wi-Fi Coexistence | MetaGeek