Two S7s here and swipe Palm to capture screen doesn't work unless you drag your hand across the screen. No way no how can I make it work if I raise my hand up slightly from the screen and try all sorts of ways of waving my hand across the screen.
In regard to your S7, you need to go Settings>Advanced Features> Palm Swipe To Capture and there turn ON Palm Swipe to Capture. Three S7's in my immediate family and Palm Swipe to Capture works well with each S7.
Palm Swipe is meant to have contact with the screen. I've done this for 2 years with my S5 and have done it numerous times in the 3 days I've had my S7. You can't "wave" your hand above the screen for a screen capture.
Monica
I IS turned ON. I just won't work unless (finally I discovered) that you have to TOUCH the screen as you swipe, rendering it, IMO, LAME. Most of the time, touching the screen during swiping literally swipes the screen to the next whatever--home screen, or whatever else is meant to display with a contact-type swipe of the screen. That's why I say the feature is LAME.
It's my understanding you use the edge of your hand to swipe, doing it this way means the page won't change.