The password change for Kasa never goes well for users.
You should report the issue to ST support also (if you haven’t already done so).
doubt I can suggest anything to assist. no pihole? try a different device with different OS… if using Android… try iOS. Again… doubt anything I come up with would have any effect. recommend ST support and raise it to a higher tier of support.
But the thing is, I also tried making brand new Kasa & ST accounts with a different email and tried linking them together and the same error came up…
The error comes up after i put in my email and password and click Authorize.
It comes up instantly like in a millisecond once i hit Authorize
got to follow up. in your first post you mentioned removing the tp-link integration. did you remove the one that shows disconnected in your screenshots or is that a listing after you attempted to link unsuccessfully?
you can link your Kasa account in the Tapo app. login with same tp-link account used for Kasa. Once you link Kasa to Tapo, try the Tapo integration in ST.
to link Kasa to Tapo… download/login to the Tapo app, tap on Me in lower menu and select Link Tapo with Kasa.
Same problem for me. My Kasa devices were working a few weeks through Smarthings and now don’t. When I try to reconnect to Tplink Kasa I too get bad request. Tried multiple things cannot get it working.
I just tried the Tapo integration and got the same results. None of my 8 Kasa devices came over to ST.
I have been using the Kasa Edge Driver for 13 months without any significant issues since the early Beta days when Barry was working out the kinks. I would retry to Edge Driver and and try rebooting you ST hub after all the Kasa devices are discovered to see if that helps.