I have a confirmed-valid audiopath URL (It's an action Output Variable from a custom Cloud Function) that simply won't play anywhere. The Cloud Function is working just fine, as confirmed in the logs. The URL audiopath returned by the cloud function works just fine, I've tested it myself in a private browser.
I first tried using the "Play Sound" action to play the sound, but that didn't work. Nothing played. I did see in the docs that the "Play Sound" action is really just for short sounds, like notification sounds, so although this sound isn't that long (it's 12 seconds) ... I thought I'd try the Audioplayer widget instead (although I want it to be invisible, which is a separate issue I'll deal with later) but suddenly the entire app is broken when I add the audioplayer widget! Although everything looks normal in the UI Builder, when I open it in run mode the entire screen is blank & gray, and when I open it in test mode I get this red screen with this error message.