How to diagnose zb smart plug going offline

Configuration Zigbee
1

I have a Sonoff S60ZBTPG smart plug, bought a couple of months ago. In the last couple of days it has been dropping offline repeatedly, even though it is only 15 feet from the coordinator and does not have any source of interference between the coordinator and itself. The coordinator is a Sonoff SMLight SLZB06, connecting via Zigbee2MQTT. While it is connected, Z2M reports an LQI of 113, which seems pretty good.
Any suggestions for how I might diagnose these disconnections, which are happening several times every day?

2

These are the last few entries for the smart plug in the Z2M log when it goes offline:

[12/1/2025, 7:07:01 PM] z2m: Failed to ping 'sonoff_iplug_lounge_tablet' (attempt 1/2, ZCL command 0xa4c13802e061ffff/1 genBasic.read(["zclVersion"], {"timeout":10000,"disableResponse":false,"disableRecovery":true,"disableDefaultResponse":true,"direction":0,"reservedBits":0,"writeUndiv":false}) failed (Timeout - 60327 - 1 - 55 - 0 - 1 after 10000ms))
[12/1/2025, 7:07:27 PM] z2m: Failed to ping 'sonoff_iplug_lounge_tablet' (attempt 2/2, ZCL command 0xa4c13802e061ffff/1 genBasic.read(["zclVersion"], {"timeout":10000,"disableResponse":false,"disableRecovery":false,"disableDefaultResponse":true,"direction":0,"reservedBits":0,"writeUndiv":false}) failed (Timeout - 60327 - 1 - 56 - 0 - 1 after 10000ms))
[12/1/2025, 7:07:27 PM] z2m: Failed to ping 'sonoff_iplug_lounge_tablet' (attempt 2/2, ZCL command 0xa4c13802e061ffff/1 genBasic.read(["zclVersion"], {"timeout":10000,"disableResponse":false,"disableRecovery":false,"disableDefaultResponse":true,"direction":0,"reservedBits":0,"writeUndiv":false}) failed (Timeout - 60327 - 1 - 56 - 0 - 1 after 10000ms))
3

Have you read this? https://community.home-assistant.io/t/zigbee-network-optimization-a-how-to-guide-for-avoiding-radio-frequency-interference-adding-zigbee-router-devices-repeaters-extenders-to-get-a-stable-zigbee-network-mesh-with-best-possible-range-and-coverage-by-fully-utilizing-zigbee-mesh-networking/

4

Yes I have previously read up on optimising ZB networks, and have taken a number of measures to optimise mine, included scattering ZB smart plugs around the house to improve the mesh network.
This particular device,as well as being a routing device itself, is also one of the closest devices to the coordinator, which is why I am puzzled by the frequent disconnections (4 times today so far).