Apologies. I meant to include those in my original post. There are no related entries that I can find in the apache logs. However, in the php_errors.log I see this a handful of times:
[18-Sep-2019 18:55:20 UTC] PHP Fatal error: Maximum execution time of 30 seconds exceeded in /var/www/osticket/include/mpdf/mpdf.php on line
31108`
If I view the mpdf.php file, this is the function in question, line 31108 is the first while:
function purify_utf8($html,$lo=true) {
// For HTML
// Checks string is valid UTF-8 encoded
// converts html_entities > ASCII 127 to UTF-8
// Only exception - leaves low ASCII entities e.g. < & etc.
// Leaves in particular < to distinguish from tag marker
if (!$this->is_utf8($html)) {
echo "<p><b>HTML contains invalid UTF-8 character(s)</b></p>";
while (mb_convert_encoding(mb_convert_encoding($html, "UTF-32", "UTF-8"), "UTF-8", "UTF-32") != $html) {
$a = iconv('UTF-8', 'UTF-8', $html);
echo ($a);
$pos = $start = strlen($a);
$err = '';
while ( ord(substr($html,$pos,1)) > 128 ) {
$err .= '[[#'.ord(substr($html,$pos,1)).']]';
$pos++;
}
echo '<span style="color:red; font-weight:bold">'.$err.'</span>';
$html = substr($html, $pos);
}
echo $html;
$this->Error("");
}
$html = preg_replace("/\r/", "", $html );