@Davepruce
Thank you for your feedback, please try to relink your Kasa devices in Alexa app as the guide here:
1. Please confirm you could control tapo device on tapo APP first locally & remotely
- Can you control the device locally (phone connected to same home network) from the Kasa app
- Can you control the device remotely (LTE or different network) from the Kasa App
2. Confirm you authorize the correct tp-link account (email), check if that is the email logged in tapo AOO
If still the same, please share a photo of error on Alexa app
Model of the router & And your network topology: e.g. Router Archer A7 <WiFi> Tapo P100