Sign in with Microsoft
Sign in or create an account.
Select a different account.
You have multiple accounts
Choose the account you want to sign in with.


In a Microsoft Exchange Server 2019 or 2016 environment, consider the following scenario:

  • You assign the Mailbox Import Export role to administrators by using the following cmdlet in Exchange Management Shell:

New-ManagementRoleAssignment -User administrator -Role "Mailbox Import Export"

  • You create mailboxes as migrated users, for example, User A and User B. (Assume that User A is User 1 and User B is User 2 in the old Exchange organization.)

  • You add the legacyExchangeDN attribute of the old Exchange organization as X.500 address to User A and User B by using the following cmdlet in Exchange Management Shell:

Set-Mailbox -Identity -EmailAddresses

  • You import the PST files into the migrated users’ mailboxes by using the New-MailboxImportRequestcmdlet.

  • You sign in to Outlook on the web (formerly known as OWA) as User A.

In this situation, you see email messages from User 2 to User 1 in Inbox. However, when you reply the email messages, you will receive an NDR message.


To fix this issue, install one of the following updates:

For Exchange Server 2019, install the Cumulative Update 2 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.

For Exchange Server 2016, install the Cumulative Update 13 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.


Learn about the  terminology that Microsoft uses to describe software updates.

Need more help?

Want more options?

Explore subscription benefits, browse training courses, learn how to secure your device, and more.

Communities help you ask and answer questions, give feedback, and hear from experts with rich knowledge.

Was this information helpful?

What affected your experience?
By pressing submit, your feedback will be used to improve Microsoft products and services. Your IT admin will be able to collect this data. Privacy Statement.

Thank you for your feedback!