Emails NON Delivery exchange 2016

Royal D Costa 241 Reputation points

am facing a unique issue with my email Server, many users are complaining that external emails are not delivered to their mailboxes, when i checked tracklogs some of the mails are already showing delivered(but not found in inbox) , but some emails are not listed in the log at all. im running exchange version 2016, kindly someone help to resolve this issue.

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,486 questions
0 comments No comments
{count} votes

Accepted answer
  1. Royal D Costa 241 Reputation points

    sorry for late reply. finally found the problem source, there was certificate error on our DNS hosting site, go Daddy, it was revoked.

    1 person found this answer helpful.

1 additional answer

Sort by: Most helpful
  1. Kael Yao-MSFT 37,676 Reputation points Microsoft Vendor

    Hi, @Royal D Costa

    Did the senders receive NDR messages indicating the mail delivery failure?

    If they didn't receive any NDR messages, and the message tracking log shows the mails are delivered, you may use the search-mailbox command to check if the mails are in the users' mailboxes.

    For example, the following command searches mails which contain "test" in the subjects in userA's mailbox and export the search results to the inbox of the administrator's mailbox. ( Don't forget to add -LogOnly otherwise the command will copy the mails to the target folder)

    Search-Mailbox -Identity "userA" -SearchQuery 'Subject:"test"' -TargetMailbox "administrator" -TargetFolder "inbox" -LogOnly -LogLevel Full  


    From the "Search Results" csv file, you may see the folder which contains the mails.


    If you can't find the mails in message tracking log, were the mails sent 30 days ago?(by default, message tracking log is kept for 30 days)
    And is it a stand-alone Exchange server or do you have other Exchange servers in your environment?

    Please also confirm if the senders receive any NDR message for the mail delivery failure.

    If the response is helpful, please click "Accept Answer" and upvote it.
    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.