Email deliverability

Question

Hello

Please i need your help on this issue.

One of my customer is experiencing deliverability issues with the email address reception@123 and has not found a solution.

The error message says “Delivery has failed to these recipients or Groups”

This message couldn’t be delivered because the sending email address was not recognized as a valid sender. The most common reason for this error is that the email address is, or was, suspected for sending spam. Contact the organization’s email admin for help and give them is error message.

Answer 1

Hi @IniobongNkanga-8038

Thanks for posting your question in the Microsoft Q&A forum.

According to your description, your customer receives the error message "Cannot deliver to these recipients or groups." "This message can't be delivered because the sending email address wasn't recognized as a valid sender. The most common reason for this error is that the email address is suspected or was suspected of sending spam. Contact your organization's email admin for help and provide them with the error message." Based on the error message, you can try the following steps to resolve the issue:

1. Based on the error message, contact your IT admin, as they can remove the user from the Restricted users page in Microsoft 365 Defender.
2. Recommended to determine if the customer's account has been compromised, then notify the admin.
3. If you are an admin, you can remove the blocked user from the Restricted entities page.
   • First, in Microsoft Defender, go to Email & collaboration > View > Restricted entities. On the Restricted entities page, identify the user account you want to unblock.
   • In the Unblock user pop-up that opens, read more about the restricted account on the Overview page. Confirm that you followed the recommendations in the Recommendations section to confirm that the account has not been compromised or to regain control of the account.
   • On the "Unblock User" page, consider the recommendations and use the links in the "Multi-factor Authentication" and "Change Password" sections to enable MFA and reset the user's password. Enabling MFA and resetting passwords are good defenses to prevent future account theft.
   After unblocking a user account, all restrictions are usually removed within an hour.
4. In addition, to better protect your account, it is recommended that you enable multi-factor authentication, change the original password in time, and enable modern authentication through the administrator to enhance security.

Refer to: https://learn.microsoft.com/en-us/microsoft-365/admin/security-and-compliance/set-up-multi-factor-authentication?view=o365-worldwide#steps-turn-on-multifactor-authentication

Enable or disable modern authentication for Outlook in Exchange Online | Microsoft Learn

https://learn.microsoft.com/en-us/defender-office-365/outbound-spam-restore-restricted-users#remove-a-user-from-the-restricted-entities-page-in-the-microsoft-defender-portal

If you have any questions, please feel free to contact me. If the answer is helpful, please click "Accept Answer" because it can help other members of the Microsoft Q&A community who have encountered similar problems and are looking for solutions. Thank you.

Best,

Jeanne