iPod touch Itouch sending but not receiving POP3 mail

[kirkandkia]

I have a new ipod touch bought directly from apple just before Christmas. We use POP3 mail accounts set up on our own server. I've set up the accounts on the Touch and I can send email on the account but when I try receiving email I get the message: Cannot connect to the server. The parameters for the mail account are identical to those on my Outlook. I ran sync for the initial set up and then manually set them up when the receive didn't work. Since we have control over the POP3 set up (i.e. no ISP or server manager) we know what should be set up for access. I spent an hour on the phone today with an Apple Expert but he didn't know what the problem was. Does anyone have any idea why receive wouldn't work when send works fine?