Article ID: 2647096 - View products that this article applies to.
Consider the following scenario:
This issue occurs because of an automatic directory synchronization issue. The DL is not assigned a prinID. Therefore, the server does not detect the users in the DL and does not send the invitation.
Note The term DL can refer to a distribution list, security group, organizational unit and so on.
To resolve this issue, install the following cumulative update:
(http://support.microsoft.com/kb/2647090/ )Description of the cumulative update for Office Communications Server 2007 R2 Group Chat server: January, 2012