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Backup Mail - Unsent Mail Guide

※ Last updated: 2025-09-08

SHIELD Mail'sUnsent MailThe menu is a screen where you can check and manage emails that could not be sent externally due to errors during the email transmission process. These emails are stored for a maximum of 2 months and will be automatically deleted thereafter.

1. What is an undelivered email?​

**What is an Unsent Email?** Email conversion was successful, but it refers to an email that failed to be sent due to an error that occurred during the process of delivering it to the recipient.

  • Transmission Path: SHIELD Mail → External Mail Server
  • Failure Causes: Conversion errors, mail server errors, etc.
  • The reason for non-delivery can be checked in detail along with the error code.

2. Menu Entry​

Backed Up Mail > Unsent MailYou can access the untransmitted email management screen from the menu.

unsent-mail

  • You can select a period (7 days, 30 days, 45 days, 60 days) and a custom period at the top of the screen.
  • SIDYou can search for specific emails by entering keywords for the sender/receiver.

3. Screen Composition​

3-1. List Table Items​

columnDescription
dateDate and time when the email was attempted to be sent
Error TypeReason for transmission failure
SenderSender's email address
recipientRecipient's email address
TitleEmail Subject
SIDUnique identifier assigned by the system (Session ID)

3-2. Detailed View​

When you click an item in the list, detailed information is displayed in the right panel.

unsent-detail

  • Transmission Error Information Tab

    • date
    • Transmission Error Types
    • Error Codes and Detailed Messages

  • Details Tab

    • Sender / Receiver
    • SID
    • Title
    • Attached file name

3-3. Unsent Error Types​

The types of errors that can be confirmed in unsent emails are as follows:

① Error related to PEP file conversion

  • Conversion result error
  • File conversion error
  • Error in generating EML based on conversion file

② Transmission-related errors

  • Mail server related errors
  • Mail Sender Related Error
  • Error related to mail recipients
  • EML transmission error
  • Unknown error

③ Reception-related errors

  • EML reception error
  • EML file creation error
  • EML Parsing Error (Format Error)
  • EML Limit Error (Mail Size, Maximum Hop, etc.)
  • Queue file creation error

It is scheduled for an update.