Question : Exchange 2003 activesync missing appointments

We synchronize Exchange 2003 with iPhones and Windows mobile devices. This works fine for email and contacts, but some calendar appointments do not show up on the mobile phones. There is nothing consistent about the appointments that go missing. Some are recurring with or without end dates. Some are non recurring. Some have multiple invitees, while others have just one invitee.

We have a lot of 3005 and 8217 errors on the event viewer in Exchange.

What could be causing the missing appointments?

Answer : Exchange 2003 activesync missing appointments

Can you run through my article, check your IIS settings, run the test on the test site for the user with the problem and report back any errors please.