@Qzaq 

The interaction logic between certain devices has been adjusted in recent product feature updates, which may affect the ability of Deco Smart Home to control some Tapo devices. Our teams are continually optimizing related features, and we recommend keeping your device firmware updated to receive the latest improvements.

If you’re unable to add this device to the Deco app, that’s likely a result of the recent updates. For now, we recommend using the Tapo app to manage your smart devices, as it offers more comprehensive features and smoother control for Tapo products.

Edit: There’s another approach that might help, but please note it could carry potential security risks. If you have concerns, we still recommend using the Tapo app to manage your device as your first choice.

The steps are as follows:

1. Ensure your Deco system is running the latest official firmware. 

2. Setup your Tapo device using the Tapo app, and enable the Third-Party Compatibility feature: go to Me page > Third-Party Services > Third-Party Compatibility. Frequently asked questions about the "Third-Party Compatibility" feature

3. Once the Third-Party Compatibility feature is enabled, factory reset the Tapo device. How to factory reset the Tapo/Kasa smart plug

4. Reconfigure the Tapo device in the Tapo app. *This step can be skipped if you don't intend to control the device via Tapo app.

5. Try to add the Tapo device again through the Smart Home section of the Deco app.