Failed to connect to back-end database. Lync Server Archiving Service will continuously attempt to reconnect to the back-end. ...

Failed to connect to back-end database.  Lync Server Archiving Service will continuously attempt to reconnect to the back-end.  While this condition persists, incoming messages will not be archived and will remain in the queue.

Database connection string : %1
Cause: Possible issues with back-end database.
Resolution:
Ensure the back-end is functioning correctly.