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There's a problem with the recipient's mailbox. Please try resending the message. If the problem continues, please contact your email admin. RRS feed

  • Question

  • Hi,

    We have a user migrated to O-365. when the user is sending email to a internet recipient, he gets an NDR- There's a problem with the recipient's mailbox.

    Please try resending the message. If the problem continues, please contact your email admin.

    Email routing involves the O-365--> on premise --> gateway. The server generating the NDR is the onpremise server.

    Generating server:onpremise server
    Total retry attempts: 3

    Remote Server returned '420 4.2.0 Recipient deferred because there is no Mdb'

    Any Thoughts?

    Cheers
    Priya


    Tuesday, April 7, 2020 4:02 PM

Answers

  • For this issue we need to check if there are any Internet recipient entry in the domain. 

    There was an AD account for which email address was added by mistake. Exchange was unable to deliver and was throwing the error. We remove the email address off the AD account and it got resolved..

    Thanks for all your help

    Cheers

    Priya

    • Marked as answer by Priya Jay Friday, April 24, 2020 9:34 AM
    Friday, April 24, 2020 9:34 AM

All replies

  • Hello,

    Did you build hybrid with O365 ?

    Did you change you domain mail as an internal relay ?  (insteed of autoritatif domain)

    Olivier

    Tuesday, April 7, 2020 5:26 PM
  • Hi Priya,

    Do you have a hybrid environment? If so, I would suggest you remove exist connector, then try to rerun HCW and choose "Enable centralized mail transport":

    In this way, HCW will configure connector for you automatically. Office 365 outgoing email will be send to Exchange on-premises first.

    Regards, 

    Kyle Xu


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

    Wednesday, April 8, 2020 6:27 AM
  • Hi Priya,

    I am writing here to confirm with you how thing going now?

    If the above suggestion helps, please be free to mark it as an answer for helping more people.

    Regards,

    Kyle Xu


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

    Friday, April 10, 2020 2:06 AM
  • For this issue we need to check if there are any Internet recipient entry in the domain. 

    There was an AD account for which email address was added by mistake. Exchange was unable to deliver and was throwing the error. We remove the email address off the AD account and it got resolved..

    Thanks for all your help

    Cheers

    Priya

    • Marked as answer by Priya Jay Friday, April 24, 2020 9:34 AM
    Friday, April 24, 2020 9:34 AM