Article ID: 2741974 - View products that this article applies to.
When the Lync Server 2010 Group Chat Channel service becomes un-operational, the symptoms listed below occur throughout the Lync Server 2010 Group Chat Server environment:
The Lync Server 2010 Group Chat Channel service requires access to a Windows Server based computer that hosts the Domain Controller (DC) Global Catalog (GC) for the Windows Active Directory Directory Services (AD) (DS) Forest. At start up the Lync Server 2010 Group Chat Channel service will connect to a DC that hosts a copy of the AD DS GC to be able to perform LDAP queries for user logons and forest wide searches. The connection between the Group Chat Channel service and this specific DC GC will remain persistent. Should this DC GC go offline the Group Chat Channel service will try to re-establish the network connection to this specific DC GC and not any other GC DC that may be available. If the DC GC is offline for a period of over 15 minutes the Group Chat Channel service will stop and the affected Lync Server 2010 Group Chat services will fail. To overcome this issue:
Monitoring, Starting, or Stopping the Channel Service
For more detailed information about Windows Active Directory Directory Services Global Catalog:
What Is the Global Catalog?
For further confirmation of this issue access the Lync Server 2010 Group Chat channelservice.exe log. For more details on channelservice.exe logging:
How to enable Group Chat Channel and Lookup service trace logging for Group Chat Server
Once you have obtained a copy of the Lync Server 2010 Group Chat channelservice.exe log search it for the following text:
ChannelService.exe Error: 0 : CRITICAL |yyyymmdd-hh:mm:ss.ms| 3: | UcmaTransport.SetAllowedDomainsForMTLS | Error in SetAllowedDomainsForMTLS. Server will no longer accept incoming messages. Retry in 60 seconds:Error querying for pools
Microsoft.Rtc.Internal.Chat.Server.ServerCommon.Squid.TrustedServicesException: Error querying for pools ---> System.Management.Automation.CmdletInvocationException: Message-"The LDAP server is unavailable." LdapError-"ServerDown" "DC01.contoso.com":"3268" ---> Microsoft.Rtc.Management.ADConnect.SuitabilityDirectoryException: Message-"The LDAP server is unavailable." LdapError-"ServerDown" "DC01.contoso.com":"3268" ---> System.DirectoryServices.Protocols.LdapException: The LDAP server is unavailable. at System.DirectoryServices.Protocols.LdapConnection.Connect()
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