We have an on-premises Exchange 2013 Server. It is installed on a Windows 2008 R2 Enterprise SP1 server, one of the 2 domain controllers in our network. Everyone is using Windows 7 SP1 Professional on the domain, with Outlook 2013.
We are facing the following situation:
There are 3user mailboxes that were created to exist just as mailboxes. There are no users that logon with those accounts. They are delegated with the "Full Access" and the "Send As" permission to 5 other physical users. These 5 other users must have full access to these 3 user mailboxes. That is why the full access and the send as permissions were granted.
The problem is that not all messages appear in the delegate's view of the mailbox in Outlook 2013. We know and we verified that because, if the user tries to logon to OWA with the delegated mailbox's credentials, all messages that would not appear in Outlook 2013, appear just fine and normally!
We have also created a SHARED mailbox and granted the same "full access" and "send as" permission to the same 5 physical users. ALL messages appear normally in Outlook 2013 for that particular shared mailbox!!
Any ideas why this is happening? Why does a shared mailbox show all of its messages while a delegated user mailbox, shows only part of them?? Is this a bug or an error in our configuration?
We are thinking of moving/converting all 3 user mailboxes to SHARED ones, so that we can see all mail flow appearing normally...
All the permissions were configured through the web-based EAC (Exchange Admin Center)
Any other ideas?
P.S. In the "mailbox delegation" section where permissions are defined, both in shared mailboxes and user mailboxes, besides the people we want to act as delegates, in the "Full Access" permission box, we have included "Exchange Servers" AND "Exchange Trusted Subsystem", in BOTH cases of mailbox type.