ISSUE
On the DualShield SSO login page, after entering the user's login name, an error "Connection Refused: connect" is returned
CAUSE
This error is typically caused by the problem that the SQL database server is not working.
If we check the das6.log file below
C:\Program Files\Deepnet DualShield\tomcat\logs\das6.log
then we should find an event similar to the one below:
If we check in the Services, then we will find that the MySQL service, MySQL(DUAL), is not running.
RESOLUTION
Restart the SQL database service and make sure it is working properly.