@Mike_1-,

All Switches and Outlets will need to have a neutral, line, and ground available to them. It is most likely that you do not have a neutral available in your wiring , as it was not required until more recent developments.

You may consider talking with an electrician to ensure that there are not hidden/bundled wires, and to see how difficult it may be to wire a neutral line to the outlet.

Try taking a look at this FAQ to see if you may have a different wiring setup and to check the compatible setups: https://www.tp-link.com/us/support/faq/1128/