Autoplaying of video's is something that unfortunately cannot be guaranteed these days. Because of changes in browser policies, autoplay doesn't always work. Muted video's do autoplay most of the time, but video's with sound will not. This results in a viewer still having to click a play-button to start the video.
When clicking through a magazine, it could happen that user interaction in the publication is noticed, causing the autoplay functionality to work (even with sound!). Unfortunately it isn't possible to assume that a browser picks up this viewing behaviour.
These limitations also apply to mobile versions and background audio/music in Pro pages. For audio there's a bigger chance it will play when there has been viewer interaction with the publication, but you would do well to test this extensively.