unable to send email to the DL

Glenn Maxwell 10,146 Reputation points
2022-12-28T21:57:32.693+00:00

Hi all

I am using exchange 2016 hybrid environment. i have a dynamic Distribution list in cloud and it has 3000 members. lets say ddl@contoso1.com.
i have mail enabled security group in onprem lets say mailenabledsecuritygroup@contoso1.com(synced to cloud)
Under the Delivery Management of the DDL i have below settings:
Only senders inside my organization
Only the specific senders will be able to send to the group: mailenabledsecuritygroup@contoso1.com

I have a shared mailbox smb@contoso1.com(created in onprem and migrated to online) which is member of the mail enabled security group.(mailenabledsecuritygroup@contoso1.com)
An application is triggering email using the shared mailbox and this application is hosted in external domain lets say contoso2.com and this contoso2.com is added as an internal relay in exchange onprem under accepted domains. When application is sending email to the DL, i am seeing the below error.

Your message couldn't be delivered
The message you sent to ddl@contoso1.com couldn't be delivered due to: Recipient email address is possibly incorrect.

Further information
5. 4.1 Recipient address rejected: Access denied.

I believe if i change the settings of the DDL to senders inside and outside my organization will fix the issue.
Is there any other way to make it work without changing the DDL settings.
currently contoso2.com is add an internal relay in onprem in accepted domains and in exchange online it is added remote domain(Allowed OOF type-external)(Automatic replies:yes)
Experts guide me.

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
4,210 questions
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.
7,369 questions
Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
1,901 questions
Accepted answer
  1. Aholic Liang-MSFT 13,741 Reputation points Microsoft Vendor
    2023-02-12T10:11:05.3633333+00:00

    Hi,

    5.4.1 Recipient address rejected: Access denied.

    when I checked the 5.4.1 error code in Email non-delivery reports in Exchange Online it shows: " The recipient's address doesn't exist.”
    274772-2022-12-29-2.png
    In addition, according to my test, messages sent by senders on the non-allow list will bounce an NDR of 550 5.7.124 instead of 5.4.1.
    Therefore, in my opinion , the reason why the mail cannot be delivered is not the setting of delivery management of DDL.
    To narrow down the issue, please also test sending mail directly to DDL using the shared mailbox to see if the messages are sent successfully.
    Besides，create a new account in contoso2.com and send a message to DDL to see if you get the same error(5.4.1)

2 additional answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Glenn Maxwell 10,146 Reputation points
    2023-02-12T09:50:20.7233333+00:00

    i dont see option to mark the answer

    0 comments
  2. Glenn Maxwell 10,146 Reputation points
    2023-02-12T09:50:56.34+00:00

    i dont see option to mark the answer

    0 comments