Unable to receive emails

[Colin]

I use a computer that connects ,via internet connection
sharing, to a computer with an ADSL line. The internet
computer can send and receive emails with out a problem.
The computer I use can send, see how many emails are
waiting on my providers computer BUT cannot receive the
emails. The settings on both computers are exactly the
same and as specified by my provider.
Does anyone have any idea what is going on

Thanks

Colin Gordon