Wrong Proxy address

Mani 261 Reputation points

Hi All,

Here I'm having an issue with Proxy address,
We are having internal users with upn@mydomain.com and external user with partner.upn@mydomain.com
Let's take an example for partner account: partner.uday@mydomain.com
When a user sends mail to uday@mydoamin.com instead of partner.uday@mydomain.com these mails need to be rejected because there is no user called uday@mydomain.com
But instead of getting the getting rejected these mails are delivered to partner.uday@mydomain.com,
I had searched the users AD proxy address and uday@mydoamin.com is nowhere added to the user.
We had checked the rules fs there is any rule that forwards messages from uday@mydomain.com to partner.uday@mydomain.com but there is no transport rule for this condition.

This is happing for all the partner accounts.

Can someone help me to sort it out.

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  1. KyleXu-MSFT 26,171 Reputation points


    First, you could use command below to check on your Exchange server, check whether this emails address exist on your Exchange server.

    Get-Mailbox -ResultSize unlimited | where{$_.EmailAddresses -match "xyz.@company.com"}  
    Get-Contact | where{$_.WindowsEmailAddress -match "xyz.@company.com"}  
    Get-MailContact | where{$_.ExternalEmailAddress -match "xyz.@company.com"}      

    Then I want to confirm with you that:

    • Do you mean add an external email address as Mail Contact on your Exchange admin center? If not, could you provide more detailed information about how do you add this external user? -
    • Whether the "company.com" is the domain name for external mail server? -
    • "This is happing for few users". What about the other user? Do you receive any NDR?

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  2. Mani 261 Reputation points


    I raised MS ticket for this issue, and they said this is because of CMT is enabled, and they suggested to turn it off.

    And I have one concern does it make any other consequences when I turn the CMT off

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