Nobody on my server is able to send email to non-local domains. For some reason /etc/relayhosts is empty which I believe is why emails cannot be sent out. Here's the error that is coming up in Outlook: Code: Task 'mail.domain.com - Sending' reported error (0x800CCC65) : 'Your outgoing (SMTP) e-mail server has reported an internal error. If you continue to receive this message, contact your server administrator or Internet service provider (ISP). The server responded: 503 valid RCPT command must precede DATA' Does anybody know how to fix this so the IP addresses will be logged in /etc/relayhosts? EDIT: I just manually entered my IP address in this file and the mail was sent out, so the problem is definately because the IPs of mail senders are not being recorded in this file.