I recently went through this above error while implementing persistent chat . To fix this error we went around circles and finally we were able to fix this permanently.

There is no single problem that can bring this error.There are so many factors that can cause this persistent chat functionality to break.

In this article i’m going to write up few factors that can cause this functionality to be broken.

Below is the error message that you will be getting when you try to enable PC functionality

Following below factors can cause the above issue:

1. Issue with SQL database connectivity:

First check  that  SQL database for the persistent chat has been created successfully. If you get             any warnings  related to SQL when you publish the topology for  persistent chat then you shouldn’t         proceed with the setup. Connect to the associated instance  from your SQL back end DB and check         if the DB is created for the newly introduced PC role. If you don’t see anything then you need to             first fix this issue.

Note: Also make sure the below configurations are set correctly on the FE,PC and SQL back-end         database server for a successful SQL DB creation.

a) Make sure the port number 1433 is open between PC role server and the back end SQL. You can            telnet to port 1433 vice versa from SQL back end to PC and check the connectivity.

b) You need to have the network discovery and enable file and printer sharing option to be turned              on in both the servers in-order for the connectivity vice versa.

c) Make sure that you have the sa(super admin) rights on the SQL instance or the server where you           are trying to create the DB for this new server.

2.  Once you publish the persistent chat server from the topology builder you need to run the lync                 deployment wizard .

Just run the first two steps alone to install the PC component roles and update them.

3. You can run the below command to set the persistent chat servers . Although this is not a                   mandatory step but at times even this can cause this problem.So its better to run this command             from Lync management shell.

Set-CsPErsistentChatActiveServer NAME -ActiveServers @{Add=”NAME_OF_PC_SERVER”} -v

4. Make sure you have the latest Cumulative Updates installed on the PC server. In my case this was   the issue. So as a thumb rule its always better to look for the latest CU’s in the persistent chat               server. Also make sure that the persistent chat services are running fine in the PC servers.

5. Final step is to go back to your Topology Builder ,delete the Chat Pool and rebuild it if none of the     above works.

Delete the chat pool that you have created from the topology builder.Then go to your deployment wizard and run install or update server system and setup or remove lync server components.

Following the above troubleshooting steps will most likely bring up the persistent chat channels in a environment.

Hope this helps

Thanks

Sathish Veerapandian

Technology Evangelist