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OnPrem Exchange 2010 Server rejects all messages from one Office365 pure cloud sender RRS feed

  • Question

  • I reaching out i the hope someone came across this issue or could shed some light.

    We are using an OnPrem Exchange 2010 SP3 in a hybrid setup.

    The issue suddenly occurred. All messages from one cloud user to internal or external recipients are rejected. The sample mail flow is like when I send from o365 to Internet, it should first go to the on-prem, then on-prem send it to internet.   But the messages seems to be rejected from the on-prem everytime. Actually we don't want to re-configure the hybrid wizard because other users have no issue. Only this specific user has this issue. I have also tested on the OWA from other machine and it can be reproduced.  It seems that on-prem server only rejects that sender.


    Here is the error

    #550 5.7.10 The e-mail account does not exist at the organization this message was sent to. Check the e-mail address before re-sending. ##

    Here is the connection encryption message

    Message sent to webmail.mydoimain.com at <myIP> using TLS1.0 with AES256

    Monday, July 15, 2019 7:22 AM

All replies

  • What is the error when the cloud user sends to an internal recipient? 

    Typically, this error indicates a security setting in your organization or the recipient's organization is preventing your message from reaching the recipient. 

    Here is an official troubleshooting link for this issue, read it carefully and you may find the solution:Fix email delivery issues for error code 550 5.7.1 in Exchange Online

    Regards,

    Manu Meng


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

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    Tuesday, July 16, 2019 3:07 AM
    Moderator
  • Just checking in to see if above information was helpful. Please let us know if you would like further assistance.

    Regards,

    Manu Meng


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

    Friday, July 19, 2019 9:35 AM
    Moderator