Hello, what is the reason that these services are obtained via https connection and not by the MAPI connection Outlook uses.

As I know, it’s because exchange includes the AutoDiscover feature that will make the services to be retrieved in a unified single location Properly configuring clients can be a very daunting task, especially for novice users. This is especially true for organizations with many desktops Most users do not know the terminology involved for all of the settings. All they wish to have is a working client and not be bothered by these things Then, AutoDiscover creates a mechanism allowing clients to automatically configure themselves. This AutoDiscover service is a web application running on IIS. All the services will be located by specific HTTP linksPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.