Cannot play sound with capacitor-sound-effects plugin in new vue project

I created a simple tabs app and want to play a sound with the capacitor-sound-effect plugin. This currently gives me an error in the console when I do ionic serve and click a button:

web.js?396d:31 Uncaught (in promise) DOMException: The element has no supported sources.

I’ve tried every relative and absolute path conceivable. I tried async/await. Now I’m trying promise handling. What am I missing?