I just received me KS225. I initially tried using the QR code in the box to add to HomeKit and I kept getting the "Unable to Add Accessory" error. I then downloaded the Kasa app to see if I could get the switch to work there. The switch was added just fine there, but I do not seem to be able to get it to add to Homekit still. 

On the TP-Link router - I have turned off 5ghz access only 2.4 is available to iPhone and KS225.  Router says the device is on 2.4Ghz network.  

I have tried Reset and Factory Reset both.  Kasa and Tapo iOS apps can both see the device.  Operates correctly with these apps.

I go to install in HomeKit - Identifies the QR code as a Light Switch (made sure the Matter numbers are correct with the QR code).

I get Unable to add acessory - Pairing Failed

Not sure what to do now.  I have operational 3 other KS225 devices that are on HomeKit and operating with apps and HomeKit correctly.

Any suggestions?