Failed to connect to back-end database. Lync Server will continuously attempt to reconnect to the back-end. While this condition ...

Failed to connect to back-end database.  Lync Server will continuously attempt to reconnect to the back-end.  While this condition persists, incoming messages will receive error responses.

Back-end Server: %1   Database: %2  Connection string of: 
%3
Cause: Possible issues with back-end database.
Resolution:
Ensure the back-end is functioning correctly.