Play mp3 in web viewer instead of downloading

Hello. I'm using a web viewer to control and stream mp3s from our server. This works great on my Apple laptop - the mp3 loads along with a player and I can listen to and control playback. It also works fine on one of two Apple desktop machines. But on one Apple desktop machine the file downloads to the desktop instead of loading in the web viewer. I've checked my browsers, both my default browser (Chrome) and the standard web browser (Safari), and the URLs play in the browser in both cases. Neither one downloads the track. Is there a way to control this behavior within FM so that the mp3 plays within the web viewer and doesn't download?

Note: The URL for the mp3s are in the format "www.url.com/assets/mp3/filename.mp3". I am loading the web viewer by using the Set Web Viewer script step and just that URL; I am not adding any additional html formatting. The only checkboxes set for the web viewer are "Allow interaction…" and "Automatically encode…"

Thanks.

Edited May 17, 20178 yr by DeathRobot