Audio files not supported on Safari 11 desktop

[po5i]

I got the response DOMError {name: "NotSupportedError", message: "The operation is not supported."} on the following HTML when I play the captcha sound:

var a = new Audio("https://xxxxxxxxxx.com/captcha/audio/52d3c6188d2fb733480ce2198a7fde4ec1e9d579");
// var a = new Audio("https://www.w3schools.com/html/horse.mp3"); // works!
// var a = new Audio("http://www.wavsource.com/snds_2017-09-17_1751672946049674/movie_stars/deniro/meet_parents_bring_u_down.wav");  // works!
var promise = a.play();
promise.catch(error => {
	console.log(error)
})
.then(() => {
	console.log('success, it played!')
})