I am seeing this error in zigbee2MQTT log. It is the Ikea repeater device. What does it mean? The repeater seems to be functioning ok. Though on occasion, a motion device that is connected to the repeater or the coordinator does not respond until almost a minute later.
Normally that indicates loss of communication to the device. If it does work, what is it’s LQI?
Mm, that’s not to bad…
Yea. I suspect the drop of connections is the coordinator (CC2531 w/ antenna) either faulty or just flaky.
How many devices do you have? The CC2531 isn’t very powerful and will start to misbehave between 20 and 30 devices (depending on the amount of traffic your devices generate).
15 devices including the repeater.
What firmware are you running ? With 15 devices it might be wise to switch to the source routing firmware.
I am assuming you are referring to the CC2531 firmware? How do I check? The seller was the one that flash it for me and I would need to get the debugger to update if I need to change firmware.
Update: I found the version tab.
I have the same error with 2 routers (repeaters), although mine are a CC2530.
Zigbee2MQTT:info 2021-06-03 21:10:00: Starting network scan (includeRoutes 'true')
Zigbee2MQTT:error 2021-06-03 21:10:12: Failed to execute LQI for 'Router comedor'
Zigbee2MQTT:error 2021-06-03 21:10:22: Failed to execute routing table for 'Router comedor'
Zigbee2MQTT:error 2021-06-03 21:10:33: Failed to execute LQI for 'Router escalera'
Zigbee2MQTT:error 2021-06-03 21:10:43: Failed to execute routing table for 'Router escalera'
Zigbee2MQTT:info 2021-06-03 21:10:43: Network scan finished
My error went away when I upgraded the coordinator to a CC2652r.
However, my initial issue still exist. It is not as frequent when I was using the CC2531 coordinator.
Though on occasion, a motion device that is connected to the repeater or the coordinator does not respond until almost a minute later.
Are those 2 repeaters fairly close to your coordinator? If you have the CC2531 and the firmware isn’t the latest, upgrade to the latest and or use the source routing firmware (network greater than 15 devices) as suggested by francisp.
I have updated the CC2531 firmware (coordinator), and removed the zigbee map add-on that was updating every 10 minutes automatically (very demanding task, apparently).
The 2 routers are now working… for the moment.
Thanks for the suggestions 
This comes and goes. Zigbee is incredibly sensitive to interference, and yes, even with an extension cable. In appartment buildings where tons of Wifi networks leak through walls, forget about it. You can try changing Zigbee channel but as soon as there’s a Wifi on similar range nearby, your stable Zigbee network is gone again.