sbs 2003 blocking pop3 emails

Hello

i have recently setup sbs 2003 server with 4 client computers.

each of the computers is now connected to the network and has internet access.

however each of the client computers has outlook installed and has an external pop3 email account.  but now all clients are receiving an error when trying to set up emails.  the outlook test shows that they successfully log onto incoming and outgoing servers, but fail on send and receive emails.

is it possible that the server is blocking this traffic.

i have not attempted to set up to allow emails and would appreciate any help in doing so.



thank you