There may be other similar errors, however due to the fact that the issue is intermittent, it may not be a Symantec Encryption Management Server issue and may be another SMTP server setting, or firewall setting having to do with SMTP.
One solution to this error is to disable the ESMTP inspection on a Cisco ASA firewall. Other versions of Cisco firewall may call this setting "esmtp fixup" and has been known to cause SMTP delays, or in the case of Symantec Encryption Management Server, may actually cause the message to not send and queue up the message.
Disabling this feature should cause mail to flow normally if a Cisco ASA firewall is being used with this ESMTPsetting enabled.
In another scenario, the Cisco firewall setting "IP inspect WAAS" being enabled can affect this behavior. Although most email may pass through properly, intermittently, the email session may be interrupted with no obvious cause. Due to the Symantec Encryption Management Server being a proxy server, the entire message must be sent to the next hop in the mail stream in order for the message to be sent successfully. If the session is interrupted for any reason, the Symantec Encryption Management Server will disconnect the session with the next hop, and the message will not be sent. The server sending to Symantec Encryption Management Server should consider the message unsent, and continue to try to send the message.
Disabling this feature allowed the emails to be processed properly without any further errors reported. Consult with your Firewall vendor for more information.
Imported Document ID: TECH165731
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