So I've got a php script that emails me a daily database backup via cron. The script will either output success or failure upon mail->send(), and it always succeeds. However, no email ever is delived if the domain name is the same (i.e. www.example.com and firstname.lastname@example.org), but if I send to another domain such as email@example.com then the script works fine. Obviously, a solution would be to just email firstname.lastname@example.org, but I'm trying to understand why I can't send emails to @example.com.
Note: It will send emails to @example.com when run from the browser. What could suppress emails to @example.com from cron and not the browser?