Microsoft Office 365 Error: "Delivery has failed to these recipients or groups"

New Contributor

Hi All,

I have one Office 365 tenant as <tenantname> While I am sending an Email from one Microsoft Office 365 Email Id to another Office 365 Email Id, then the error is appearing as: "Delivery has failed to these recipients or groups, Your message wasn't delivered because the Recipient's email provider rejected it". 

Like I was trying to send email from user1@<tenantname> to user2@<tenantname>


You can see the error message as shown in the below screenshot. Below represents my Office 365 Email Id format which I have provided:


Can anyone suggest to me how I can resolve this issue?


outlook error.png



7 Replies

@Preeti321 The Error clearly confirms, that due to Too many Spam email sent on the specific domain has been Flagged, and Tagged on SpamHaus (Global Directory) for IP Blacklisting. Additionally you should not be sending emails form (Tenant Address) and instead should use Custom domain name. this not only tags your Tenant address as Blacklisted (for Spam Abuse) but also blocks specific IP (outbound) through which emails are relayed over to Internet.


Cheers !

Ankit Shukla


I didn't send any Email to anyone yet. Can you tell me where I can check the Email information whether I will check in the Exchange admin center or anywhere else?@ankit shukla 


1. you can check for Mail Traffic Report in Security & Compliance Center - (using your Global Admin Access) 

2. You can also go to Exchange admin Center (  ) using your Global Admin and then Navigate to Protection < Action Center for your Blocked Users (from sending emails)

3. Delist IP and Tenant from Block using this URL -

4. If issue still persists, then reach out to Microsoft Support to unblock IP and Tenant restrictions from Backend.


Cheers !

Ankit Shukla




I have checked it already. There is nothing in the Restricted Users as you can see in the above screenshot.

One more thing I can tell, This is a new tenant that I have created recently.

@ankit shukla 

best response confirmed by Preeti321 (New Contributor)

@Preeti321  Any specific reason you want to send emails from your Tenant Address and not your own Custom Domain ?


Please go through FAQ for Domain in Office 365 -


Additionally, are you a Microsoft Vendor (working for Support Projects) worldwide? If yes - Please reach out to your Technical Advisor for unblocking the Test Tenant you own, internally !!


If not, and you are only using it for your Own Learning and testing, you should not use address for sending emails (except) testing.


Please delist your Tenant and IP by opening a Microsoft Support ticket.


Cheers !

Ankit Shukla



@Preeti321 Your welcome, please mark as answer , if it resolved your issue :)