Dompdf 0.8.3没有在PHP 7.2和CodeIgniter 3中获取远程CSS

Question

I'm upgrading my environment to PHP7.3 (from PHP5.5) and my DomPDF new installation (from 0.6 to 0.8.3) does not fetch any external CSS files. All server-related configuration seems ok, but only relative CSS files are loaded.

What may I be missing?

I'm using the following lines to generate the PDF:

require_once("dompdf_0-8-3/autoload.inc.php");

$options = new Dompdf\Options();
$options->set(array('isPhpEnabled'          => true, 
                    'isRemoteEnabled'       => true, 
                    'isJavascriptEnabled'   => false, 
                    'isHtml5ParserEnabled'  => true, 
                    'tempDir'               => sys_get_temp_dir())
        );

$dompdf = new Dompdf\Dompdf();
$dompdf->setOptions($options);    
$dompdf->loadHtml($html);    
$dompdf->setPaper($size, $orientation);            
$dompdf->render();
$dompdf->stream($filename.".pdf");

Note: I'm using base_url() in link href's tag, inside the HTML view.

Anyone has the same problem or any suggestion on how to solve?