Symptom: After installing the Persistent Chat module for Lync Server 2013, you receive the following error when trying to manage Persistent Chat from the Lync Admin Web GUI (CSCP).

1 Warning(s) All the channel servers are down.

Solution: Unfortunately, there are a few issues that could cause this.  Here are a few that I tried to get things working.

Solution #1: Ensure Cumulative Update 2 is installed.

1. Download a copy of the Lync Update on the persistent chat server
   1. http://www.microsoft.com/en-us/download/details.aspx?id=36820
2. Double click LyncServerUpdateInstaller.exe
3. Click the Install Updates button
   
4. Once all the updates have finished installing, click Close
   
   

Solution #2: Add only 1 server to the pool, then add the rest

1. Login to one of your front end servers and open up the Lync Server 2013 Topology Builder
2. Delete the persistent chat pool you currently have deployed
   
3. Publish your topology
   
4. Recreate your persistent chat pool, but only add 1 server during the setup wizard.
   
5. Once done running through the wizard, right click on your persistent chat pool and select New Server...
   
   1. Repeat this until all the servers you wanted to deploy are part of the topology
6. Publish the topology
   

Notes: I couldn't get event viewer to log anything referencing this error, which I thought was weird.   Additionally, I noticed that when originally deploying my topology, the topology wizard was complaining saying that "At least one machine must be active." in order to successfully deploy the persistent chat pool.  I believe this is a bug in the topology builder and the only way I could get the topology builder to deploy properly, was by following Solution #2.  This ensured at least one server in the pool had a machine state marked as "Active".

Here is a screenshot showing the persistent chat servers in an enterprise pool marked as inactive and topology builder complaining with the error "At least one machine must be active."