Galaxy S6 playing notification sound even though notifications are OFF

My galaxy s6 keeps playing the notification sound every second or two. I went to make sure notifications was turned off, thinking somehow an update had turned them back on. However my notifications setting is already set to off. I can't get it to stop playing the sound and I do not know what other setting to try. I tried turning notifications on, moving the apps set to give them all to off, then setting notifications to off again. That made no difference. Help!

Welcome to Android Central! Do the sounds correspond with a new notification in your status bar? If not, try turning off NFC and see if that gets rid of the sound.

Didn't work! What else??