Can not synchronize to exchange server

[Tim]

I can sync all Outlook 2000 folders with my corporate
Microsoft Exchange Server when using a dial-up connection
thru my VPN. However, when I switch to my cable modem thru
my VPN and syncronize Outlook to the Microsoft Exchange
Server, I can not get anything in my Outbox to transport
to the server. The synchronization process hangs up on
sending. I have to close outlook and go back to the dial-
up to complete the synchronization.

Why the differences and what do I need to change to make
the synchronization work while using a high speed internet
connection.

Thanks,

Tim