The rss xml output gets a ; in the xml header, thus making the xml invalid.
The problem is that the end question mark int the string is output with ; ?>
You can use this code in modules/Rss/views/rss.php to fix it
<?php
header('Content-Type:application/xml');
?>
<?php
$questionmark = "?";
echo "<".$questionmark."xml version=\"1.0\" encoding=\"utf-8\"".$questionmark.">";
?>
The rss xml output gets a ; in the xml header, thus making the xml invalid.
The problem is that the end question mark int the string is output with ; ?>
You can use this code in modules/Rss/views/rss.php to fix it