I’m trying to switch my single pole light switch to a Kasa Tp-link single pole wifi smart switch. I’ve moved the wires over exactly how they were from the original to the new. Now the cabinet lights blink on and off when the breaker is turned back on. I’m not able to turn them off without flipping the breaker.
Anyone has this issue before?
A regular light switch is very forgiving on the distinction between line and load. You need to be sure you have the wire that goes to the fixture on the load wire of the Wi-Fi switch and the hot on the line wire.
It’s great that you took before pictures, those are always useful. But please, whenever you get a smart device, follow the wiring instructions in the user manual for that device. It’s actually quite rare for the wiring to be identical to the old dumb device. Because there is a radio inside a Smart device, it Has to get power, and that tends to change the way things get hooked up. So start with the user manual and then if you have any questions about the wiring, contact the device manufacturer. There is a very real fire hazard if you wire things in incorrectly, at a minimum you might short out your brand new device. 
This email exchange has been extremely unhelpful and a waste of time. Don’t bother replying.
