Currently I'm working on a small C# application reading data from Outlook and Exchange and I decided to share some of the things I find - that can be interesting bahaviour or some API information. When starting to work with Oulook make sure you can resolve the hostname for Exchange. In Outlook's configuration dialog you can enter an IP adresse and authorization works but any further operation will try connection to Exchange using the hostname and fail with some random error message if that's not possible.