Zigbee Unreliability Issues

So I’ve had issues in the past with Zigbee devices disappearing and not reappearing after a battery change, but this new issue is even more egregious;

I added 4 new (identical) Zigbee plugs. Currently one lives in one room, another in another room, and two next to each other in a third room. After a day or so, only one of them actually responds anymore, the other 3 have just “gone dark”. They are still powered on and active.

Any ideas why this is happening? It’s incredibly annoying. I was on a Sonoff Zigbee dongle in the past but have recently moved to a SLZB-MR4U, though both have had the same issue.

Also one of them shows as Battery rather than mains too which is in itself weird.

Versions for what it’s worth:
Zigbee2MQTT version
2.7.0

Frontend version
2.4.2

zigbee-herdsman-converters version
25.80.0

zigbee-herdsman version
7.0.1

Machine
#1 SMP PREEMPT_DYNAMIC Tue Nov 4 13:52:04 UTC 2025 - 6.12.51-haos - x64
CPU: Intel(R) Core™ i5-8259U CPU @ 2.30GHz (x4)
RAM: 15995 MB

Node version
v22.16.0

Coordinator
EmberZNet

Edit: It shows 4 offline now as between when I originally wrote the report and now when I took the image, the last one has gone offline too.

Maybe it is the plugs that are the problem and not the other parts.

Have you checked what your TTL is for devices in Z2M?
And what the report interval is for your plugs?
Have you checked for new firmware or but reports on the plugs?
The vendor should have a webpage with support information. If it without support then that is likely your cause to the problems.

Not sure what you mean by TTL in this context. The passive timeout?

One of the plugs actually managed to update to a new firmware before dying, not sure about the others.

Vendor support just covers the basics. They don’t really cover much once it’s already paired with a Zigbee coordinator.

Yeah, it was the passive timeout.
Try to increase it and see if that helps.

And a good vendor should do support if there is a problem with the plug even though it is paired with a Zigbee coordinator.

These are active devices as they are mains powered, not passive and the timeout is already 1500 minutes which is huge - they should be reporting every few seconds so it is absolutely not the passive timeout responsible for this.

I’ll try the vendor support.

EDIT: Why do I have to wait 5 minutes between forum posts? Peak inconvenience, jesus.

I think it is a spam protection mechanisms.
It should be removed fast if you just stay active on the forum.