Are you able to see your cron task in your server control panel, or do you have a record of the task that was set up? If so, try copying and pasting the dailymail password from the task into the ListMail Configuration page.
If you can edit the task, try setting up "email output" to your email address, then remove the output suppression from the task, ie:
With output supression:
0 0 * * * /usr/bin/wget -O /dev/null -T 0 http://example.com/mail/dailymail.php?pw=YourDailyMailPass 1> /dev/null 2> /dev/null
Without:
0 0 * * * /usr/bin/wget -O - -T 0 http://example.com/mail/dailymail.php?pw=YourDailyMailPass
When dailymail runs, you could be sent an email with a "permission denied" or other error which could indicate your host has changed permissions on the "wget" utility used by the task.
Regards