@Endy29 

I just did this tonight and it worked great. In my case the pool light was controlled by a breaker switch. When I pulled off the panel, I saw the breaker switch went to a standard outdoor eletrical outlet on the side of the pool panel box. The pool light was wired into the electrical outlet. Explains why I thought the outlet didn't work because I never tried it with the pool light on. So I cut/spliced the pool light hot wire from the outlet switch, wired in the the two black wires from the HS200 to each end of the freshly cut hot wire (after stripping a bit on each end of course). Then as you state, wired the ground to the ground block and the white to the neutral block. Once I finished the wiring and flipped the breaker switch back on, the HS200 switch started blinking orange and green and I was able to join it to my network via the app. Working great through Alexa now. Added an automatic shut off schedule late in the evening for when the kids forget to turn the pool light off.

In  your case, I would verify the previous wiring. Was the pool light wired directly into the breaker? If so you might need to turn the breaker switch on and leave it on for your HS200 switch to start working. Another option would be to leave the current wiring in place, but simply splice the hot wire to the pool light like I did. Basically inserting the switch into the hot wire running to the pool light.