Laravel Error

        // create new DOMDocument object
        $dom = new DOMDocument();
        // Fix possible whitspace problems
        $dom->preserveWhiteSpace = false;
        // CAS servers should only return data in utf-8
        $dom->encoding = "utf-8";
        // read the response of the CAS server into a DOMDocument object
        if ( !($dom->loadXML($text_response))) {  <--  !!!!!!!!!!! THIS LINE IS HIGHLIGHTED !!!!!!!!!!!!!!
            // read failed
            throw new CAS_AuthenticationException(