Exchange migration internal delivery. What have I done wrong?

Brad Lamont 0 Reputation points
2023-07-27T05:43:59.6233333+00:00

I am migrating an Exchange installation from 2013 to 2019 which has gone smoothly until now. I have migrated my first test mailbox but email is not delivering to the mailbox when on the new server. Regardless of which server catches the email, it goes into the queue on the old server and fails to deliver with a DNS error, the next hop domain in the message queue being the MDB on the new server.

Current server Version 15.0 ‎(Build 1497.2)‎

New Server Version 15.2 ‎(Build 221.12)‎

Queue viewer

Next hop domain DB02

Delivery type: SMTP Delivery to mailbox

Last error: 451 4.4.0 DNS Query failed. The error was: DNS query failed with error ErrorRetry

Exchange Server
Exchange Server
A family of Microsoft client/server messaging and collaboration software.
1,434 questions
0 comments No comments
{count} votes

1 answer

Sort by: Most helpful
  1. Jarvis Sun-MSFT 10,221 Reputation points Microsoft Vendor
    2023-07-27T09:09:02.7533333+00:00

    Hi @Brad Lamont ,

    Thanks for posting in our Q&A forum.

    According to the error code, one article I found suggests that this issue occurs because the DNS service cannot be used if the Register this connection’s addresses in DNS check box is not selected in an Exchange Server 2016 or Exchange Server 2013 environment. Reference: https://learn.microsoft.com/en-us/exchange/troubleshoot/mailflow/dns-query-failed-error-when-email-stuck-in-draft

    Another article suggests that if Exchange 2019 was installed into an existing site and the SCP was temporarily moved to Exchange 2013 or set to NULL, it needs to be updated. Depending on your configuration, you should point the SCP to either the internal FQDN of the Exchange 2019 server or to your load balanced namespace. Reference: https://techcommunity.microsoft.com/t5/exchange-team-blog/best-practices-for-migrating-from-exchange-server-2013-to/ba-p/3773084

    Hope the above can help!


    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.


Your answer

Answers can be marked as Accepted Answers by the question author, which helps users to know the answer solved the author's problem.