@Rickdog99 

Good day.

Did you only replace upstairs dumb switch whose outlet has neutral wire with a single HS210?

And currently, the problem is :

There is no response for the light when you press the downstairs switch?

There are some tips to check the wires：

Each HS210 has 5 wires: two travelers, one ground(not necessary), one neutral (provide power for itself), live or load wire(if one HS210 is connected to live, the other HS210 would be connected by load).

So if you press the physical switch on HS210, then press again, the big round circle would be off then back on white, the switches have itself powered properly; ----so you did not miss the neutral wires for both;

More details about the wires：https://www.tp-link.com/support/faq/2009/

Thank you very much.

@Brook

HI Brook

I replaced upstairs dumb switch that had the neutral wires already bundled with one single HS210 unit.   As for the downstair switch, it does stil turn on and off the light.  The problem I am having is the HS210 switch upstairs makes the light click on and off repeatdly with the amber/orange color reflected on the unit.  I have the read the FAQ and am stumped.  I could try to hook the unit into the downstairs dumb switch and it has the 2 travelers, no ground, a wire that appears to be a neutral wire not currently plugged into anything, and the live/common wire.  Thanks.