All Zigbee devices lost connection

I have a mix of Zwave and Zigbee devices. Recently all Zigbee devices lost connection with the V2. Smartthings hub. All Zwave devices continue to work properly.
Had switch plugs and water leak devices on Zigbee. Some plugs show still connected but do not respond to commands. Others show offline. Tried to remove and reinstall a few plugs and water leak sensors. The hub does not find any of the removed devices. Error code 34-302. Can add new Zwave devices without issues.
Did not change anything to cause the disconnect that only affected Zigbee devices. Any ideas? Contacted support and after about an hour the issue was referred to higher tier… Waiting for call back.

They can diagnose and help

Have you tried power cycling the hub? Make sure to take the batteries out of your v2 hub to power cycle it correctly.

The Hub was cold rebooted twice with batteries removed. The Zwave devices came back and the Zigbee devices remained disconnected. This all happened quite suddenly and affected all Zigbee devices. The smart plugs have been functional for several years, while the water leak sensors have been functional for 8 months and one for just a few weeks. All the Zigbee devices paired quickly and without any issues until now.
Thinking the Zigbee driver may have become corrupted, but original support didn’t follow that track.
Smart Plugs - Seedan M001 seen as eWeLink SA-003 (four)
Water Leak- Centralite 3315C (one)
Water Leak - Thirdreality 3RWS18BZ (one)

Problem solved.

Support reported that the error message indicated that the Zigbee device could not be paired due to interference. Suggested to relocate the hub away from my router. Seems that WIFI and Zigbee share the same 2.4 GHz band. That worked and allowed the devices to be again paired with the hub.
My router was sent to AUTO channel config and must have changed channel to one that interfered with Zigbee. I set router to use fixed WIFI channel 2 on the low end of the band. Set Zigbee from channel 20 to channel 24 at the high end of the band. Also relocated the hub further away from the router.
Hopefully this will continue to operate properly.


-First that support found out that interference problem
-And this router thing. All this will be in my (Evernote) how to Zigbee etc. (incl the 20 minutes shut down trick.)
Happy for you!