Sporadic users reporting incoming emails are not being received


  • On occasion we get end users not receiving emails from customers. Sometimes asking the customers to resend the emails works fine but sometimes we simply do not receive any email from customers. I have setup no inbox rules, I have read the logs and there are messages of bounce back or receiving email from the customers. The customers do type the correct email address verified by screen shot and sent to an end users personal email. Can someone help and give me some clues on what the issue maybe?
    Friday, June 16, 2017 5:20 PM

All replies

  • Hi

    As per your problem you need to checkout your mail Gateway first if you MX and public DNS you have configured properly.

    On mail Gateway you can check that the customer email is landing to your mail Gateway or not ?

    If mail is landing, what action is being taken by your Gateway ? Gateway action will help you to troubleshoot the exact issue with your customer email such is mail is being Allowed, Blocked, Deferred or what action is performed ?

    If its being blocked at your mail Gateway you can further dig out on the logs about the reason of blocking or Deferred.

    You also need to check the Spam rate control level if you configured and SPF record, PTR records.

    You can check Exchange queue from powershell & GUI both if you see mail is queued there.

    If everything is well configured at your end then you need to check with sender your customer Gateway may be blocking your domain emails or something goes wrong at customer end.

    There are many reasons which are involved and needs to be verified in mail flow. You can check one by one and dig out the issue.

    Kindly click "Mark as Answer" on the post that helps you, this can be beneficial to other community members reading this thread.



    Friday, June 16, 2017 11:26 PM
  • Hi,

    Does this issue only affects the customer’s domain or randomly and also other domains?

    And please make sure if this issue affect specific customers?

    Please check if you have any block list about the customer.

    Collect and post out the NDR messages in detail if exist.

    You can check the Protocol log for the affected customer or users via the following steps:

    1) Run following command to enable protocol log on all the send connectors on that Exchange server.

    Get-receiveconnector | Set-receiveconnector -protocollogginglevel verbose

    2) Try to reproduce the issue.

    3)Collect the latest SMTP log from following location on that server:

    C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\Logs\FrontEnd\ProtocolLog\SmtpReceive

    If any error messages, please post out for further troubleshooting.

    Hope it helps.


    Jason Chao

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    Tuesday, June 20, 2017 7:55 AM