Attempting to release messages from the Messaging Gateway (SMG) Spam Quarantine fail with the following error in the BrightmailLog.log file:
Apr 28 2022 12:44:21 [https-jsse-nio-443-exec-4] [QuarantineManager] ERROR - error.quarantine.unable.release.delivery
com.symantec.smg.controlcenter.internal.mail.transport.MailTransportException: Cannot release mail, cannot connect to any available MTA service. ; nested exception is:
javax.mail.MessagingException: Unknown SMTP host: smtprelay.example.com;
Component : Control Center
The SMG Control Center is unable to resolve the configured SMTP relay host in the DNS