I recently upgraded to Exchange 2007. We do not use cached mode. When a user using Outlook 03 sends a mail it will stay in the outbox until they either click another folder or the polling interval of 60 seconds hits and they get a clump of messages.I have read a lot on the topic, but no one has an answer. Everyone says to disable the Windows firewall. We have that disabled. They say to disable Symantec, we dont use it. It seems as if the UDP packet is not reaching the Outlook clients for new mail notification.I have seen people say to use a static port for UDP communication. Tried it. Doesnt work.Is there an actual solution to this or does Outlook 2003 not communicate with Exchange 2007 for new mail notifications?Thanks.