Send HTTP GET request with Basic authentication token

Question

I am trying to fetch information from a site with basic authentication (username and password), I followed documentation and some forums here, but I can't get it to work.

Whenever I run the function, it returns the HTML from the login website, as if the authentication isn't working.

function getRequest() {

var url = "URL";
var username = "USER";
var password = "PASSWRD";

var headers = {
    "Authorization" : "Basic " + Utilities.base64Encode(username + ":" + password)
};

var params = {
  "method":"GET",
  "headers": headers
};
    
const response = UrlFetchApp.fetch(url, params);

Logger.log(response.getContentText());

}

I need it to return the contents from the website already logged in.