Current Calls may continue, but with reduced functionality

Recently I have seen many cases where a client are facing issues in which MOC reconnecting again and again & goes into loop of Sign in/Sign out with error “Current Calls may continue, but with reduced functionality”. Sometimes users are getting log off continuously and sign-in on MOC or Lync after several reboots.

Causes: The issue occurs because the Office Communicator 2007 R2 users getting moved between different pools servers.

Resolution: 

Basically users who were having this issue may them moved recently between different pool server and their config file was pointing towards OLD pool server.

Most of the times it is resolved by a reboot or multiple reboots, but sometimes (when user is working remotely) it doesn’t get resolve then try to locate the file “EndpointConfiguration.cache” under the location %userprofile\Local Settings\Microsoft\Communicator\Sip_username@domain.com and delete that, client should reboot their workstation and then try.

Details: The Office Communicator 2007 R2 client updates the user's EndpointConfiguration.cache file when the user signs out of the Office Communications Server 2007 R2 pool. If the sign-out process is interrupted, the EndpointConfiguration.cache file cannot be updated with the secondary Office Communications Server 2007 R2 pool’s FQDN and TCP port information. This causes the Office Communicator 2007 R2 client to do the following:

Try to automatically sign in to the Office Communications Server 2007 R2 pool by using the legacy FQDN and TCP port information that is listed in the EndpointConfiguration.cache file

Time out and not connect because the original Office Communications Server 2007 R2 pool front-end servers are offline

Perform a DNS lookup for the SRV records that are configured for the automatic sign-in process

So, please compare the entry in EndpointConfiguration.cache and user’s allocated pool, if difference is found then better delete that else he may face the issue while working remotely.