I have multiple sites on this server, under two different users. On one, the mail function is working how I intend -- actually emailing the subject. On the other, the email isn't going out (I'm not getting a PHP error on the page or in my log), but it is giving me an alert on command line
You have new mail in /var/mail/jake.
I installed the mail server a while ago (I think it was Postfix or something), and it works on one domain. Is this a user issue or something that's letting it work in one but not the other?