Solved same issue.
I bought 1 Nous A1Z for test. Worked as expected.
After that I bought a 4-pack on Amazon. Two plugs tested, they started pairing, are recognized but keep blinking. During pairing device is functional. After pairing timeout not functional anymore.
Removed first working device by accident, also did not pair correct anymore.
The solution which worked for me:
- Remove all zigbee devices (had only 3), also disconnect from power
- Remove Conbee II / ZHA integration
- Shutdown HA platform (in my case Virtual Machine on Synology NAS)
- Restart HA platform
- Conbee II / ZHA is discovered, configure it as before
- Open device Zigbee Coordinator (= Conbee II stick)
- Click on: ‘ADD DEVICES VIA THIS DEVICE’
- Plug on power of first device
- Device starts pairing, is recognized correct and working
- Repeat this for all your devices, in my case all of them are pairing correct
I expect the trick is to start the pairing by ‘ADD DEVICES VIA THIS DEVICE’. After 1 failed device no other one can be added correct. By removing the whole integration I expect the storage of failures is also removed and with that the issue solved.
Just my expectation, but I got it working without complete reinstall.
Hope this helps for everyone with the same issue.