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Exchange Server 2016 451 4.4.0 DNS query failed. the error was:SMTPSEND.DNS.NONEXISTENTDOMAIN DOMAIN RRS feed

  • Question

  • I keep getting this message in Exchange 2016 queue. The next hop domain name is listed as the exchange database name (db01) and I'm not sure why.

    Therefore the error pops up with non existent domain (db01) and the messages just sit there. How do I remedy this issue?

    Do I need to create a send connector for db01?

    Monday, February 11, 2019 7:10 PM

All replies

  • Im starting to think its a DNS issue. 
    Monday, February 11, 2019 8:59 PM
  • Hi,

    Are these internal emails or External?

    Do a nslookup for mx record of domain where you are sending emails from Exchange server.

    https://support.microsoft.com/en-in/help/3038746/451-4-4-0-dns-query-failed-exchange-server-error-in-message-queue


    Thanks, Ashish (I can be wrong but can't be rude) “Tell me and I forget, teach me and I may remember, involve me and I learn.” MCITP, MCT, MCSE. Please remember to vote and mark the replies as answers if they help.

    Monday, February 11, 2019 9:15 PM
  • external email. nslookup was correct.
    Monday, February 11, 2019 9:34 PM
  • Hi,

    Use the External DNS Lookup settings on the transport server on the send connector.

    Also check which setting configured under dns lookup (in ECP click on server->Edit->External dns lookups). Make sure that all available IPv4 is there.


    Thanks, Ashish (I can be wrong but can't be rude) “Tell me and I forget, teach me and I may remember, involve me and I learn.” MCITP, MCT, MCSE. Please remember to vote and mark the replies as answers if they help.

    Monday, February 11, 2019 9:45 PM
  • Hi,

    The error basically means that the source server attempts to contact to the next hop server but failed to do so for some reasons.

    You can check the network settings in Exchange server. A similar issue is solved by removing alternate DNS server from TCPIP properties. You can refer to the blog and see if the solution helps.

    Exchange 2013: 451 4.0.0 DNS query failed

    Please note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information. And the changes made in the above blog is not supported officially by Microsoft.

    Regards,

    Dawn Zhou


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams. 

    • Proposed as answer by Dawn Zhou Thursday, February 21, 2019 9:54 AM
    Tuesday, February 12, 2019 9:54 AM
  • Hi,

     

    How is everything going? If there is anything unclear or any update, please feel free to post it here. If you have solved the issue, please mark the solution as answer, which could be beneficial for answer searching in the forum.

     

    Thanks for your understanding.

    Regards,

    Dawn Zhou


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams. 

    Thursday, February 21, 2019 9:55 AM