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Email getting bounced back RRS feed

  • Question

  • Okay, so I've setup Exchange 2016 and had to create additional accepted domains under mail flow - accepted domains. Well, one of the domains I setup is working fine. I can send/receive emails. The other domain, domain B is not working. The user is not able to send/receive email. If I send an email to the user@domainb.com, I get a bounce back.  Here is the error:

    Diagnostic information for administrators:

    Generating server: cal1-mh676.smtproutes.com


    Remote Server returned '< #5.0.0 smtp; Failed to resolve MX records for domain B; response=records:[], arec:false, nshost:192.69.16.12, success:false, code:3, err:host not found, attempts:0, nanos:1533082>'

    I've looked at the queue viewer and can see those emails I'm sending getting stuck. I never had to do anything special for Domain A.  Domain B is setup as an authoritative domain type. 

    Any help would be appreciated.

    Thanks

    Monday, January 2, 2017 7:40 PM

Answers

All replies

  • Okay, so I've setup Exchange 2016 and had to create additional accepted domains under mail flow - accepted domains. Well, one of the domains I setup is working fine. I can send/receive emails. The other domain, domain B is not working. The user is not able to send/receive email. If I send an email to the user@domainb.com, I get a bounce back.  Here is the error:

    Diagnostic information for administrators:

    Generating server: cal1-mh676.smtproutes.com


    Remote Server returned '< #5.0.0 smtp; Failed to resolve MX records for domain B; response=records:[], arec:false, nshost:192.69.16.12, success:false, code:3, err:host not found, attempts:0, nanos:1533082>'

    I've looked at the queue viewer and can see those emails I'm sending getting stuck. I never had to do anything special for Domain A.  Domain B is setup as an authoritative domain type. 

    Any help would be appreciated.

    Thanks


    Who is getting these NDRs? Internal or External senders?

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    Monday, January 2, 2017 8:16 PM
  • Ah, it's only external senders. Internally, the user can send all day with no issues.
    Monday, January 2, 2017 10:13 PM
  • I would suggest using the inbound SMTP tests on https://testconnectivity.microsoft.com/Sounds like you are missing external DNS records.

    • Marked as answer by Todo1997 Tuesday, January 3, 2017 12:37 AM
    Monday, January 2, 2017 10:25 PM
  • Ok, I know what the issue is now. I ran the inbound SMTP tests which failed. No MX records found in DNS. I have to make the changes in DNS and add the MX records for Domain B. That should fix the issue.

    Thanks

    Tuesday, January 3, 2017 12:36 AM