We might not need to contact the host... If dailymail works then I recommend double-checking bounce.cgi (ListMail URL, permissions, etc) and attempting a manual email with TESTBOUNCE in the subject (then check for returned mail containing an error).
The following code, entered to a .php file, uploaded and browsed to, will show the exact owner and permissions of the wget utility:
<?phpecho shell_exec("ls -al /usr/bin/wget");?>
Also, please double-check that the bounce address does not exist under standard mailboxes - it must only exist as an email forwarder.
Regards