My setup: ZHA with Bitron Video Silicon Labs EmberZNet protocol Stick
I’ve just spent nearly 2 x days trying to reconnect my Xiaomi Temperature and Humidity Sensor to HA.
Everytime I started the pairing the LED flashed and I started the pairing sequence, but it would just not connect. I even pulled out my old Smartthings which it had worked on last year and it would not connect to Smartthings either.
I also checked the voltage of the battery which was 3.00v which I thought was fine, as it uses a CR2032 3v cell.
However as a last resort I tested a new battery and that measured 3.3v so I tried a new battery and it then paired first time.
I hope this avoids others wasting lots of time trying to pair these devices