iPhone 4 Will not Sync Calendar through Exchange Server 2003 I have an iPhone 4 that I can't seem to sync to our corporate Exchange server (Exchange Server 2003). Email syncs fine, however generally calendar items do not sync, and when they do, they disappear from the phone after about an hour.

I've re-added my corporate account to the phone, attempted to sync via WiFi rather than 3G, and I've checked all settings to ensure that they are correct. Corporate policy states that iPhones are not to sync with iTunes, instead using only the mobile Exchange server.

Do you have any advice?
According to Apple's Exchange ActiveSync and iOS Devices:Requirements iOS devices support Exchange ActiveSync (EAS) for Exchange Server 2003 Service Pack 2.

Check with your Exchange Administrator and be certain that your system meets that requirement. The linked document may be of further assistance.