If you have, for example, a cronjob executed every 2 minutes, this means that you will receive an email with the cron result every 2 minutes.
To prevent the sending of email notification, add any one of the following lines at the end of each cronjob command:
>/dev/null 2>&1
or
&> /dev/null
Example:
/usr/bin/php /home/www/my-best-domain.com/mail.php >/dev/null 2>&1
or
/usr/bin/php /home/www/my-best-domain.com/mail.php &> /dev/null
