@Riley_S It appears that the wiring in my house is identical in all 4 boxes but only one of the boxes works in this situation - the Kasa dimmer fails to connect from the other 3. Is this because (for...

I have 4 switches I am installing (into boxes that were former Belkin dimmers!). The first one, on one floor, went in with no issues. Number 2, 3, and 4 are located in an older part of the house but...