Process ForefrontActiveDirectoryConnector.exe (PID=1928). WCF request (Get Servers for chickbuns.com) to the Microsoft Exchange Active Directory Topology service on server (TopologyClientTcpEndpoint (localhost)) failed. Make sure that the service is running. In addition, make sure that the network ports that are used by Microsoft Exchange Active Directory Topology service are not blocked by a firewall. The WCF call was retried 3 time(s).

Error Details 
 System.ServiceModel.EndpointNotFoundException: Could not connect to net.tcp://localhost:890/Microsoft.Exchange.Directory.TopologyService. The connection attempt lasted for a time span of 00:00:02.0280035. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:890.  ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:890
   at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
   at System.ServiceModel.Channels.SocketConnectionInitiator.Connect(Uri uri, TimeSpan timeout)
   --- End of inner exception stack trace ---

Log Name:      Application
Source:        MSExchange ADAccess
Date:          1/13/2014 8:57:01 PM
Event ID:      4027
Task Category: General
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      DC4.chickbuns.com
Description:
 Error Details 
 System.ServiceModel.EndpointNotFoundException: Could not connect to  net.tcp://localhost:890/Microsoft.Exchange.Directory.TopologyService. The connection attempt lasted for a time span of 00:00:02.0280035. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:890.  ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:890
   at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
   at System.ServiceModel.Channels.SocketConnectionInitiator.Connect(Uri uri, TimeSpan timeout)
   --- End of inner exception stack trace ---

Hi

Is the service running as indicated in the error? Any firewalls locally or AV? exclusions setup?

Only windows default firewall

Hi,

According to the detail of the error, we can try the following resolutions:
1. Check if there is some Windows firewall rule blocking certain port.
2. Check if youre having trouble allowing other computers to communicate with your computer through Windows Firewall, and you can try using the Incoming Connections troubleshooter to automatically find and fix some common problems.
In Windows7, Open the Incoming Connections troubleshooter by clicking the Start button Picture of the Start button, and then clicking Control Panel. In the search box, type troubleshooter, and then click Troubleshooting. Click View all, and then click Incoming Connections.
3. Check if there is some service which doesnt work.

If you have any question, please feel free to let me know.
Thanks, 

Enable IPv6 if it's disabled. Also make sure that your AD Subnet is configured properly as per your Exchange environment.

Resolved this by enabling IPv6. Thanks a lot.