Ikea tradfri Outlets falling off the network

[tabnul]

What happened

I have a zigbee network with 10 ikea tradfri outlets, 2 osram lights and 3 ikea lights and 20-ish xiaomi sensors.
Some of the Ikea Tradfri Outlets falling off the network every now and then, just a single device every time. The rest keeps working.
All devices are updated to the latest firmware. (outlets 2.0.024)
Dont have logging currently (just put it on debug), but the devices just become unavailable (not responding to availability pings) and stop reporting by themself.

power cycling the device fixes the issue.

I am not sure whether this is related to zigbee2mqtt or to the actual hardware. it happens to both old outlets (2018/2019) and brand new ones. I cannot find the issue online for people that use the tradfri gateway, so maybe a combination issue?
Then again i would expect this to also happen to the lightbulbs of ikea (assuming same chips/firmware)

What did you expect to happen

Devices to stay connected.

How to reproduce it (minimal and precise)

Not able to reproduce. Just have to wait a few days/weeks for one to fall off the network.

Debug info

Zigbee2MQTT version: 1.14.4
Adapter hardware: cc1352p-2
Adapter firmware version: 20200805

Below my configuration.

{ "external_converters": [], "devices": "devices.yaml", "groups": "groups.yaml", "homeassistant": true, "permit_join": false, "mqtt": { "base_topic": "zigbee2mqtt", "server": "mqtt://core-mosquitto", "user": "ZZZZZZZZZZ", "password": "ZZZZZZZZZZZ" }, "serial": { "port": "/dev/ttyACM0" }, "advanced": { "availability_timeout": 900, "report": true, "log_level": "debug", "pan_id": 6759, "channel": 21, "last_seen": "ISO_8601", "network_key": [ ZZZZZZZZZZZZZ ], "availability_blocklist": [], "availability_passlist": [] }, "device_options": {}, "blocklist": [], "passlist": [], "queue": {}, "experimental": {} }

[tabnul]

i want to add the remark that i did not have this issue a year ago when i was using less devices with cc2531 and obviously older zigbee2mqtt version.
Maybe it is related to amount of devices, amount of traffic, routing configuration, or something else?

[tabnul]

After reading the linked post above i started looking at my link quality and it looks like that some routers have very poor range directly to the coordinator. Especially some of the routers that i saw dropping off the network.

However those routers are in the same room as other routers. They have 200+ link quality with those neighbour routers.
Those neighbour routers on their turn have respectable link quality with the coordinator.

So basically, the mesh itself is healthy, but router/outlet > coordinator is not always healthy.
Could this cause them to drop off sometimes? Doesnt make sense to me..

[Koenkk]

To debug this I would recommend sniffing the network and identify the timeframe they drop off as narrow as possible. (https://www.zigbee2mqtt.io/how_tos/how_to_sniff_zigbee_traffic.html).

[tabnul]

Thanks Koen, i will wait for it to happen again.
I relocated the coordinator slightly and changed the channel to 25 and this at least increases link quality. Lets see if this fixes the issue. Wouldnt make sense for me but lets see.

[tabnul]

Edit: one of the tradfri outlets just went offline. Going to try to sniff the network. But it only happens every so often so will be a challenge.

[tabnul]

Ok, it seems to be an issue with the outlet placement in my case.
The outlets that gave issues were sitting next to eachother in the power strip, without any room in between.

Since i replaced them to have a few centimeter space in between i havent seen them falling off the network. Also no LQI failed messages anymore in the logs! Also , my xiaomi sensors seem to be more stable, probably because their routers are having less distortion.

Could it be that placing routers near each other causes signal interference?

Anyway doesnt look like to be a zigbee2mqtt issue ;)