Instagram Bot Auto Follow Back

function IG_followBack() {
  var url = "https://api.fadhiilrachman.id/instagram/respondFollowBack.php?",
  opt = {
    "method": "GET",
    "payload": {
    },
    "muteHttpExceptions": true,
    "followRedirects" : true,
  },
  username='YOUR_USERNAME_HERE', password='YOUR_PASSWORD_HERE';
  UrlFetchApp.fetch(url + 'username=' + username + '&password=' + password,opt);
}