My following jquery function always execute Error block of alert but js.i-parcel.com is available

why My following jquery function always execute Error block of alert but  js.i-parcel.com is available..

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<script type="text/javascript">
  $(document).ready(function() {
  });
  function checkIparcel() {
    $.ajax({
      type: 'GET',
      url: 'https://js.i-parcel.com',
      timeout: 15000,
      success: function(data) { alert('Connected to i-parcel.'); },
      error: function(XMLHttpRequest, textStatus, errorThrown)
      { alert('Error:\r\n' + textStatus); }
    });
  }
</script>

https://js.i-parcel.com site is available , Still control goes into error block please help..