After months of frustration, I finally solved the issue with my SmartThings hub and Matter over Thread devices. Here’s my story in case it helps someone else:
I have over 125 Matter over Thread devices running on my SmartThings hub, and everything was working perfectly for over a year. Then, suddenly, all 125 devices went offline, and my Zigbee devices stopped working too. I tried everything—rebooting the hub, resetting the network, checking firewall rules, even adding explicit IPv6 configurations. Nothing worked. My house was literally dark.
After a few days, everything started working again, but I knew it was just a temporary fix. A few weeks later, it happened again—over 100 devices went offline, and I couldn’t get them back online for over a week. My wife was not happy!
Finally, I stumbled upon a forum post mentioning conflicts between SmartThings and Hue hubs. I had never considered the Hue hub as a culprit, but I decided to unplug it for a few hours. Within minutes, my SmartThings devices started coming back online. It was like magic!
It turns out there was some kind of conflict between the Hue hub and the SmartThings hub. I’m not blaming Hue—it’s been great otherwise—but it just happened to be the culprit this time. Hopefully, this helps someone else avoid the same frustration!
If you’re experiencing similar issues, try disconnecting other hubs or devices temporarily to see if they’re causing the problem. It might save you a lot of time and stress.