- you have no audio on slide 1 => the storyline "play" button don't appear before start course
- you jump from slide 1 to slide 2 without a user click
- you jump from slide 2 to slide 3 without a user click
- no audio on slide 3 because the browser is blocking audio, because no user click was before
solution:
- add on your slide 1 a short audio e.g. on an unused layer
- now storyline adds a play button before the course => audio is playing on all following slides
https://community.articulate.com/discussions/articulate-storyline/video-autoplay-not-working#reply-860502
more infos:
https://community.articulate.com/discussions/articulate-storyline/audio-is-not-working#reply-904680