Event ID 5377 is logged on a Lync Server 2010 Group Chat server Content provided by Microsoft Applies to: Lync Server 2010 Standard EditionLync Server 2010 Enterprise Edition Select Product Version All Products Symptoms The following event is logged in the Lync Server log on a Microsoft Lync Server 2010 Group Chat server: Cause This issue occurs if you create a user in Active Directory Domain Services whose distinguished name contains more than 256 characters, and then you add this user to a distribution group. Resolution To resolve this issue, install the following cumulative update:2514984 Description of the cumulative update for Lync Server 2010, Group Chat: November 2011 Note After you apply this update, the Group Chat server supports users whose distinguished names contain up to 384 characters. Last Updated: Dec 15, 2011 Can't find what you're looking for? Search No results Did this solve your problem? Yes No Tell us what we can do to improve the article Submit Thanks! Your feedback will help us improve the support experience.