Ok this is clearly related to user registrations because everytime a new registration occurs, this email is sent to the Admin. Correct me if i am wrong, but the Admin is supposed to get an email when a new user registers right?
The new user is getting thier confirmation email, but the admin is not getting his hence the cron email that reads
Cron <acpftp@*****> cd /var/www/vhosts/***.*****.com/httpdocs/periodic; /usr/bin/php -q cron.php
"sendmail: fatal: No recipient addresses found in message header"
So it cannot find the admin email address to send the New Registration notification? But it knows the Admin email to send this cron error email?????!!! Huh?