Shoutcast get metadata XMLHttpRequest cors

Question

I am trying to read this Shoutcast metadata with XMLHttpRequest: http://cast10.plugstreaming.com:8002/stats?sid=1&json=1

When I try this I get "has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.". I already have cors, so why does it throw that error?

var xhr = new XMLHttpRequest;
xhr.onerror = function (e) {
     console.error(xhr.statusText);
};
xhr.onreadystatechange = function () {
           
};

var url = 'https://kastproxy-us.herokuapp.com/' + 'http://cast10.plugstreaming.com:8002/stats?sid=1&json=1'

xhr.open("GET", url, true); 

xhr.send();