Email rejection

Question

My customer keeps getting this message when trying to reply to my email.

[Moderator note: personal info removed] 

If you sent this message to multiple addresses, you'll receive a notification like this for every one that didn't arrive.

Answer 1

Please note that our forum is a public platform, and we will modify your question to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.   

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Hi @carlos Castro

Thank you for sharing your concerns.

You could refer to AI’s suggestion, this issue appears to be related to a DNS configuration issue on the sender’s side. As a result, Microsoft has blocked these emails because their dare considered insecure or do not meet required trust or authentication standards. 

 

You can refer more via: Fix NDR error "550 5.7.515" in Outlook.com - Microsoft Support 

To resolve this issue, I recommend contacting the sender through an alternative method (such as phone or direct communication) and asking them to verify and correct their DNS configuration, or to seek assistance from their email service provider. 

Once the DNS records are properly configured and stabilized, the sender should be able to successfully deliver emails to your account. 

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

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Answer 2

The error is a non-delivery report (NDR) with code 550 5.7.515. This means Outlook.com / Microsoft consumer services (MSN, Hotmail, Live, etc.) are rejecting messages from the sender’s domain (WEBERLOGISTICS.COM) because it does not meet the required email authentication level for high‑volume senders.

From the NDR text:

• Spf = Pass
• Dkim = Fail
• DMARC = Pass
• Error: 5.7.515 Access denied, sending domain WEBERLOGISTICS.COM doesn't meet the required authentication level. The sender's domain in the 5322.From address doesn't meet the authentication requirements defined for the sender.

Microsoft has introduced stricter authentication requirements for large‑volume senders to Outlook.com and related consumer services. When those requirements are not met, messages are rejected with 550 5.7.515.

Action is required on the sender’s side (WEBERLOGISTICS.COM), not the MSN recipient:

1. The mail/domain administrator for WEBERLOGISTICS.COM must review and correct the domain’s email authentication configuration (SPF, DKIM, DMARC) so that it meets Microsoft’s high‑volume sender requirements.
2. Specifically, DKIM is failing; the admin needs to:
   • Ensure DKIM is correctly configured and enabled for the domain used in the 5322.From address.
   • Ensure the DKIM signing domain aligns with the From domain as required by DMARC and Microsoft’s policies.
3. After the domain’s authentication is correctly configured and aligned, new messages from WEBERLOGISTICS.COM to Outlook.com/MSN/Hotmail recipients should be accepted instead of rejected with 5.7.515.

Until the WEBERLOGISTICS.COM email administrator fixes the domain’s authentication, replies from that customer to the MSN address will continue to bounce with this error.

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References:

• Fix NDR error "550 5.7.515" in Outlook.com
• Security Operations guide for email authentication in Microsoft 365
• Sent email in Outlook.com comes back "delivery failed"