You have configured email alerts for Symantec Data Center Security (DCS). You see the notification generated for the alert (in the Notifications tab under Monitor in the UMC) and all the email configuration settings are correct, yet emails are not received.
'Client was not authenticated' in the sis-alert.log file
The mail server used is not set to accept non-authenticated outbound email from the DCS manager
Enable 'TRACE' logging for sisalertlogger.loglevel=TRACE in the sis-server.properties file (default location: <Install Dir>:\Program Files (x86)\Symantec\Data Center Security Server\Server\tools\wizard\scripts).
Restart the DCS Manager services & wait for a new notification to be generated (related to the email alert created).
Browse to <Install Dir>:\Program Files (x86)\Symantec\Data Center Security Server\Server\tomcat\logs & check the sis-alert log file for error mesages.
Once you see the email sent in this log, DCS has done its part, the Customer will have to troubleshoot his environment. The most common issue is the error: 'Client was not authenticated' Example:
187770 2018-11-01 03:16:11.682 [WARN ] [Timer-12678:14,076] Unable to send email. Subject: testswift com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.1 Client was not authenticated
In this scenario, the customer has to ensure that the mail server must accept non-authenticated outbound email from the DCS manager.