The server is running Server 2003 Enterprise Service Pack 2, with Exchange 2003 SP 2. Currently all e-mail seems to be working except for one mailbox which can only receive internal e-mails, not external. I checked the message tracking center when I sent from my gmail to the account in question and it looks like everything is normal. I checked her Outlook and it is working. I even logged in through Outlook Web and it does the same thing. There are no rules created. At this point, not sure what to do.