I'm at a bit of a loss then. My agent's email isn't getting messages, but two other agents on the same domain are (that domain is not what osticket is living on, if that matters). If I change Admin's Email Address (in Emails > Settings) then I'll get them at the address I changed it to, and the other two folks still get theirs. Other than email addresses and names, all three OSTicket accounts are set up identically.
I've tried setting my agent's email to something bogus, and got an error message on the SMTP server's account, so I'm wondering if everything is going out fine (with my initial setup) but my recipient's mail server is being numb. It's Outlook, so it could be, it's just weird that only my address is having issues.