You may encounter following error when you try to login in Group chat console after Group Chat server installation…

"cannot sign in because of a problem with the chat room service. if the problem persists, please contact your system administrator."

Ensure that the certificate assigned to Group chat service is correct. The certificate used for Group chat server should have Group chat server name (FQDN) as its subject name. The certificate’s EKU should have client and server authentication. Root CA certificate chain must be installed properly.

Following accounts should be member of RTCUniversalServerAdmins. These accounts should also be member of local administrators group on the group chat server. Super User account to be used to sign-in the Group Chat Admin Tool has Local Administrative Rights or equivalent.

GCChannel: Service account for Channel Server
OCSChat: Service account for automatic login.
GCwebservice: Service account for Web Service
GCCompliance: Service account for compliance Service
GCAdmin: Service account for Group Chat Server

Note: These Group Chat Service Accounts should be present with proper permission.

Enable the intended admin account along with the above five service accounts for
SIP on OCS Pool.

Ensure that the Group chat accounts have right permission on the SQL server… Follow this link to ensure this. http://www.ocspedia.com/GroupChat/Preparing_Infra_for_GC.htm

Under Group Chat admin sign in console => Edit Accounts Settings => Automatic
Configuration => Uncheck "Use my Windows credentials to log in automatically" => then
under Office Communications Server leave Host "blank", select encrypted radio
button (If DNS has SRV and Host records to facilitate Automatic Configuration) =>
under Group Chat Server Settings leave “Use default server address” box unchecked
and for “Server Address” enter "OCSChat service account" unless if otherwise using
custom named Lookup Service account name.

If you still have problem, collect Group Chat server logs. By default you’ll have Group Chat Admin tool log under %userprofile%\Application Data\Microsoft\Group Chat\Admin Tool\Logs.

See following URL to know how to enable additional logging for Group Chat server…

http://www.ocspedia.com/GroupChat/Group_Chat_Logging.htm

You might see following error in the Group chat console or Admin tool…

<resp code="440">No channel server is available.</resp>

You need to start the channel service, if it is already started then restart it.