Attempting to release some messages from the Messaging Gateway (SMG) Spam Quarantine fail with the following error in the BrightmailLog.log file:
Dec 07 2021 12:22:33 [http-nio-443-exec-10] [QuarantineManager] ERROR - error.quarantine.unable.release.delivery
javax.mail.MessagingException: Could not connect to SMTP host: xyz.com.sg, port: 25;
nested exception is:
java.net.ConnectException: Connection timed out (Connection timed out)
The SMG Control Center web application cannot connect to the destination host on port 25 to deliver the message.
This may be the result of either an incorrect setting in Administration > Control Center > SMTP or an intermediate firewall disallowing the SMG Control Center from connecting to the destination mail server to deliver the message.
If Administration > Control Center > SMTP is configured to use a specific destination host, please ensure that the configured destination host is both accessible and running and SMTP server.
If Administration > Control Center > SMTP is configured to use the existing non-local relay settings please confirm that firewall rules allow the SMG Control Center host to make SMTP connections to the destination domain's SMTP servers.