Hi, You cannot log in Kasa app or the Google assistant App? If you cannot login google App any more, it may have something to do with your google account. May contact google to get some advice....

Hi, Can you do that with your old two way switch? You may need to wire those two switches together, but I don't recommend you do that unless you've done that before with electrician.

Hi, What's the operating system of your computer? And what's the hardware version of your T6E? How far is the computer away from your router? Do you get good Wi-Fi signal? And how slow it is? You may...

Hi, Check it out https://www.tp-link.com/en/faq-2231.html

Hi, No, it cannot use power from USB.

Hi, It's just one part of the establish of PPPoE connection between the modem and your ISP. They exchange data to negotiate then finish the installation.