Delivery has failed to these recipients or groups:

Question

I suddenly started getting these messages today, when emailing with people I have emailed with before and new. Multiple different people so its not that their inboxes are full. I even get it when I tested email my own private email.

Even get it when trying to send out meeting invitations.

What can I do?

Delivery has failed to these recipients or groups:
Your message wasn't delivered because the recipient's email provider rejected it.

Answer 1

Hi @Sageo ,

Before we go on, could you clarify the things below so that we can understand better about the situation?

1. Which kind of email account are you using, Outlook.com, Microsoft 365 for Business or Microsoft Exchange?
2. Are there any error code or additional information aside from the error message you shared earlier? You can check the "Diagnostic information for administrators" section of the non delivery report to see if there are any findings. If you are uncertain about what to check, you may remove all persoanl information involved such as domain name, email address, etc, and then share the information here.
3. Since you've added the office-outlook-itpro tag which is for general issues in Outlook desktop client, so are you sending out emails via the Outlook desktop? If this is the case, it's suggested to try sending messages via the web mail and check if the error persists, this helps narrow down if the issue needs to be further invesitaged from the email account rather than the client side.

In addition, based on my research, sometimes this error may occur when the sender's IP address is blocked, so if possible, you can try testing with different devices and see the result.

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Delivery has failed to these recipients or groups:

******@dut.edu.vn
Your message wasn't delivered because the recipient's email provider rejected it.

-For about a week now, my organization's email can't be sent out

Answer 3

My organization uses Office 365 Email with domain name:
******@dut.udn.vn