Site mailboxes allow users to work together naturally – while compliance is applied behind the scenes. A site mailbox brings Exchange emails and SharePoint documents together. For users, a site ...
Updated Jul 01, 2019
Version 2.0
Blog Post
Site Mailboxes are supported with Outlook 2013 Preview. You need to make sure that you are listed in the SharePoint's owner or member group as a *individual user* (not through security groups). Then Site Mailboxes will show up in your Outlook navigation after the next Outlook start or within a few hours (whichever occurs first).
Hope that helps,
Alfons