I have a very weird problem with Outllook 2003 connecting to Exchange 2003 SP2 over VPN. Outlook in Cached mode.
Even though VPN speed is quite good (browsing network, downloading files etc.) then, when it comes to the Outlook, it can take even 10 minutes (!) to download 500 KB mail. Over that time it's poping up with "Outlook is trying to retrieve data from the Microsoft Exchange Server ..." every now and then. Probllem is also vidible while browsking public calendars - sometime Outlook can open calendar, and few seconds later hang for some time ("not responding" for few minutes...) .
Have no idea what's wrong, user says it started friday evening. Was trying alternative broadband services with no effect. :(