none
Reply from External users to a Distribution list containing external users

    Question

  • Hi,

    I have a Office 365 exchange online hybrid setup having a distribution list containing external contacts and internal contacts.

    * When user from my organization sent email to DL no issue

    * When user from outside our domain sent emails to this DL, email delivers to my organization members but sender receive bounce back for external contacts.

    This issue was not there earlier however we are facing sine last 15 days.

    More Info for Email Admins

    Status code: 550 5.4.355 When Office 365 tried to send the message to the recipient, it couldn't find the recipient's domain name (external.com) in the Internet's Domain Name Service (DNS) directory. If the sender spelled the domain name correctly, it's likely that only the recipient's email admin can fix this problem. Contact the recipient's email admin and give them the error (including the name of the server that reported the error) found in the "Error Details" section below. Suggest they contact their domain registrar to make sure their domain is correctly set up and that their DNS records have replicated across the Internet. Unfortunately, it's unlikely Office 365 Support will be able to help fix this issue.

    Original Message Details

    Created Date:

    04-05-2018 11:04:15

    Sender Address:

    user@external.com

    Recipient Address:

    another user@external.com

    Subject:

    Test email 

    Error Details

    Reported error:

    550 5.4.355 Remote server returned recipient domain does not exist -> 553 #5.1.8 Domain of sender address <user@external.com> does not exist

    DSN generated by:

    HE1PR0602MB3353.eurprd06.prod.outlook.com

    Remote server:

    Friday, May 4, 2018 5:45 PM

All replies

  • Hi Rameshwar,

    This does not seem an issue related to your Exchange organization. 

    As the error information mentioned: If the sender spelled the domain name correctly, it's likely that only the recipient's email admin can fix this problem. Contact the recipient's email admin and give them the error (including the name of the server that reported the error) found in the "Error Details" section below.

    Please follow the suggestion in "More Info for Email Admins" .


    Best Regards,
    Niko Cheng


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


    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Monday, May 7, 2018 3:22 AM
    Moderator
  • Hi Rameshwar,

    Is there any update on this thread? If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well. Thanks for your understanding.


    Best Regards,
    Niko Cheng


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


    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Monday, May 14, 2018 10:10 AM
    Moderator