From: DeskNow Knowledge Base
http://www.desknow.com/kb/

Error during validity check of database connection. The connection may be broken. Closing and creating a new connection.
http://www.desknow.com/kb/idx/7/010/article/

This message may appear if you're using an external database, and the connection to the database is broken for some reason. DeskNow will detect this, and automatically try to recreate the connection.

Note that MySQL by default closes client connections that have been inactive for more than 8 hours, so this message may very well appear in the morning. This is nothing alarming, as generally DeskNow reestablishes the connection transparently. To avoid this, you can also set your my.ini configuration file (it's in C:WINDOWS in Windows systems), and set/add the following lines:

set-variable = wait_timeout=315360000
set-variable = interactive_timeout=315360000

and restart MySQL.

Other reasons for this message may be that the database server has been restarted, or that a network problem occurred between DeskNow and the database.