Next button is inactive until end of slide

I created a course about a year ago where the Next button does not become active until the audio on that slide is completed. I am trying to turn that off now, and I can't figure out how! (I don't remember how I set it up to begin with) There are no triggers on the slides (except to advance to the next slide when the Next button is clicked), so I am stumped! Any ideas where else this would be set up?