After I added the persistent chat role to a Standard Edition Front End Server the service was stopping unexpectedly.
There was an error in the event viewer 53503 Unexpected DB Version
I ran the Lync Update Installer and noticed that the persistent Chat role was not up to date
I started the persistent chat service again and the issue was resolved the service was starting and running. whoohoo!!! time for a brew !
So remember when adding Lync roles to run the appropriate cumulative update straight way !