"Your message wasn't delivered because the recipient's email provider rejected it." How do we fix this?

The error message you are encountering indicates that the recipient's email provider is rejecting the messages sent from your new Outlook account. Here are some steps you can take to troubleshoot and potentially resolve this issue:

1. Check the Recipient's Email Address: Ensure that the email address you are sending to is correct. A typo in the email address can lead to rejection.
2. Review Email Content: Sometimes, specific content in the email can trigger spam filters. Avoid using excessive links, attachments, or spam-like language in your message.
3. Verify Domain Reputation: If your sending domain has a poor reputation or is blacklisted, emails may be rejected. You can check your domain's reputation using various online tools.
4. SPF, DKIM, and DMARC Records: Ensure that your domain has the correct SPF, DKIM, and DMARC records set up. These records help authenticate your emails and improve deliverability.
5. Contact Recipient's Email Provider: If possible, reach out to the recipient's email provider to inquire why the messages are being rejected. They may provide specific reasons or guidance.
6. Test with Different Recipients: Try sending emails to different addresses (especially those outside the domain) to see if the issue persists. This can help determine if the problem is specific to one recipient.
7. Check for Throttling or Restrictions: If you are sending a large volume of emails, your IP address may be throttled. You can refer to Microsoft documentation on throttled traffic for more information.

If these steps do not resolve the issue, consider reaching out to Microsoft support for further assistance.

References:

• Microsoft 365 throttled traffic from my IP address

Since this forum is a public platform, so we have modified your question to hide your personal for privacy. For future posts, kindly avoid sharing personal or organizational information to protect your data. 

Hello @DivDoc ,  

Thank you for reaching out to the Q&A forum! 

To support you better, please provide me more detail: 

1.You shared the error message, however, if possible, could you provide a screenshot of the error? 

Note: I will help you blur or hide any personal information if needed. 

2. Could you check your Outlook account settings by going to Outlook => File => Account Settings => Email and share a screenshot? 

Based on the information you provided, it seems your email might be sent through a hosting server. If your account type is POP/IMAP, please make sure you have configured Microsoft 365 SMTP settings: 

 For reference: How to set up a multifunction device or application to send email using Microsoft 365 or Office 365 and POP3 and IMAP4 in Exchange Online | Microsoft Learn 

3.Are you using a personal account (Hotmail/Outlook.com) or a work/school account (managed by your organization)? 

4.If you are using a work or school account, have you checked your domain in Microsoft 365 Admin Center? Is the domain status showing as Healthy? 

5.Also, have you configured SPF and DKIM for your domain? 

You can infer these articles:  

• Set up SPF identify valid email sources for your Microsoft 365 domain - Microsoft Defender for Offi… 
• Set up DKIM to sign mail from your cloud domain 

Please understand that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to identify the root cause and find a solution.             

Looking forward to hearing from you.     

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