@Robert3230 can you post pictures of the switch and the box wiring before and after?

@Kathie68 Your Welcome Glad to be of help

@Kathie68 If you removed one of the white wires from the group of whites, that was the wrong step. Put that white wire back in the group and add the white from the HS200 to the group of white wires.

@YanivHS Yes, connect the HS220 white to the two White wires in your drawing.

@Blusmbl You should measure from ground to each lead. Then flip the switch and measure any lead that showed 0volt before. I have not used other products.

@Blusmbl As your wiring diagram shows the neutral goes directly to the light fixture. You do not have a neutral at the switch boxes.