@munchthewizard
Thank you for reaching us.
Please confirm it's a two-way environment where 1 switch operates 1 light.
- Correctly wiring HS200 requires at least 3 lines in your electrical box
1*Live wire, 1* Load wire, 1* Neutral wire, 1*Ground Wire (optional)
- Kindly note that if No Neutral Wire is present, HS200 can Not be installed.
Here is HS200 installation video that may help : https://www.tp-link.com/support/download/hs200/v1/
It is possible that the neutral wire is missing o, it is recommended to consult a qualified electrician to check wires & wire modification.