first, your src='' is illegal. protocol missing. webview doesn't know what you want (http, https, etc)
and even after you add the protocol, you trigger a cors violation.
i gather you want to play music or some medi, but you can't do it like you're doing.
you should try to run your html in chrome on your desktop and then look at the developer's tab. you'll see exactly what the error is.
webview is not chrome. some things that work in chrome do not work in webview.