Consider the following scenario:
You sign in to the Microsoft Lync Server 2010 Group Chat Administrator Tool.
You try to add a user who is in a nested distribution list or in a distribution list that contains several members to a chat room. To do this, you start to type the name of the user in the Add User to Role dialog box, and then you click Search before you have typed the complete name.
In this scenario, the Group Chat Administrator Tool does not display the search results. Additionally, you receive the following error message:
Unable to get eligible principals: Operation failure
This issue occurs because of a time-out error that occurs when the Group Chat Administrator Tool performs a Lightweight Directory Access Protocol (LDAP) search in the Active Directory database within the distribution list. The time-out value for a search is 15 seconds.
To resolve this issue, install the following cumulative update:
2670342 Description of the cumulative update for Lync Server 2010, Group Chat: February 2012 After the update is installed, the time-out value for searches is set to 120 seconds.