Applies to SharePoint Calendar E-Mail Extension 3.0 and Meeting Organizer 1.0 (SharePoint 2010)
This post contains some in depth information about the SharePoint Calendar E-mail Extension.
When you activate the Event (with e-mail extension) content type in your calendar list, the Calendar E-Mail Extension registers an e-mail receiver to handle replies (accept, decline …) sent from invitees.
The list now sends invitations to attendees and handles responses but it will no longer accept meeting requests sent to the list.
Calendar E-Mail Extension changes the way your SharePoint Calendar list handles e-mail. To give a brief overview:
That’s why the list now can’t receive meeting requests.
Please download and install the Meeting Organizer Add-On: http://www.sapiens.at/en/products/pages/sharepoint-calendar-e-mail-extension-meeting-organizer.aspx
In a nutshell, after you install the “SharePoint E-Mail Extension 3.0”, to allow a calendar list to receive an incoming e-mail meeting requests you need to install the “Meeting Organizer Add-On”. (Thanks Scott)