When attempting to simultaneously release a large number of messages from the Messaging Gateway (SMG) Spam Quarantine, the control center interface can become sluggish and the session time out.
[http-41443-Processor5] ERROR - error.quarantine.unable.release.delivery com.sun.mail.smtp.SMTPSendFailedException: 421 Too many errors on this connection---closing
We have seen issue with Internet Explorer (IE) 8 on older Windows OS versions such as Windows 2003.
Please update to a newer version of IE, or use a different browser such as Chrome or Firefox. As a workaround, you can limit the number of simultaneously released messages to under twenty.