"5.2.1" or "5.2.1" NDR when sending large attachments in Office 365 Dedicated/ITAR


In Microsoft Office 365 Dedicated, you do not receive email messages that include large attachments. Additionally, one or both of the following symptoms occurs in this situation:
  • You receive a non-delivery report (NDR) that states that the message is too large (NDR code 5.2.1 or 5.2.3).
  • The sender does not receive an NDR.


This issue occurs when one or both of the following conditions are true:
  • A message size limitation is set on the sender’s mailbox, or a limitation policy is set on the sender’s email server.
  • A message size limitation is set on the recipient’s email server.


To resolve this issue, reduce the message size, and then resend the message. To reduce the message size, use one or more of the following methods:
  • Use compression technology, such as WinZip.
  • Split the attachment into multiple files that can be sent separately.
  • Use other technologies such as FTP or Internet File Sharing (such as OneDrive) to share or transport large files that do not require high security or data encryption.
If you do not receive an NDR, Microsoft Support Services may have to conduct additional message tracking to determine the cause of the issue. Collect the following information, and then use the Exchange Online topic and the Mail Routing sub-topic when you submit a support incident online to Microsoft Online Services Support:
  • Message subject
  • SMTP sender/recipient
  • Date/time sent

Or, contact Microsoft Online Services Support by telephone .

Ідентифікатор статті: 2519303 – останній перегляд: 17 січ. 2016 р. – виправлення: 1

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