After a series of power cycles (~3 from a power outage) all of my matter devices have stopped working. This entity is no longer being provided by the matter integration. If the entity is no longer in use, delete it in settings.
This has happened to me before when messing with POE and I had to reset each device and repair them. Anyone have any ideas on how to get the matter administration working again?
Connecting 2 Nest Thermostats, Eve Motion, and a Nano Leaf light strip.
Maybe restart Matter AddOn.
Did you by change upgrade Home Assistant beyond 2023.12.2?
Is there a problem with HA beyond 2023.12.2 that could cause this? This has happened to me a few times, and I can’t figure out why. It’s been working solidly for over a month. Then stopped last night at some point. All Matter devices just un-paired. No HA update happened last night… ?
Did you get anywhere with this?
Following up here, any progress? I have matter bulbs in by bathroom on regular switches, so they power cycle all the time. After maybe 10+ cycles, one becomes “unavailable” and won’t come back until I repair.
I am bizzarly in a similar boat. One of my matter devices (Orvibo Switch) apparently went offline 3 days ago:
light.master_bath_exhaust_fan became unavailable
11:33:12 - 3 days ago
I just rebooted the device to see if that would help. Also restarted HA to see if anything changed and no luck.
This is annoying because I have a middle of the night automation tied to the exhaust fan. If the fan is on (taking a shower - triggered from humidity sensor), then don’t turn off the lights. If you go to the bathroom in the middle of the night, my lights turn on to 9% dim just so you can see where you’re going and then I turn them off 2 minutes later, but I am leveraging that switch (which now became unreliable) for a condition.
We noticed it this morning because the lights never turned off in the bathroom after going back to bed 
I’m new to Home Assistant, migrating a bunch of devices from Homekit to Home Assistant about 3 weeks ago. It’s been rock solid till yesterday, when this issue cropped up. I have about 20 matter devices, and yesterday, after performing some electrical work where I had to turn some electrical circuits off, I had about 10 matter devices become unavailable. Trying to figure out what I need to do to repair these items and get them back online.
Well, I hope this isn’t a regularly occurring issue. I spent a good part of the day un-configuring/re-configuring the unavailable matter devices.