Outbound email failing

Question

Hello

Please i need your help on this issue.

One of my customer is having an issue with Outbound email failing.

Outbound messages to other Microsoft 365 Tenants are failing after a 24 hour deferal.

See 2 samples below

 

Sample 1

Message ID: ******@IA1PR19MB6547.namprd19.prod.outlook.com Sender: paul@XXXX

Recipient: Corey@XXXX

Submission Time (UTC): 02/12/2025 10:05AM

Rejection Time (UTC): 02/13/2025 10:05AM

Fail Error: Reason: [{LED=550 4.4.7

QUEUE.Expired; message expired};{MSG=};{FQDN=};{IP=};{LRT=}]

 

 

Sample 2

Message ID: ******@IA1PR19MB6547.namprd19.prod.outlook.com Sender: paul@XXXX

Recipient: aperry@XXX

Submission Time (UTC): 02/10/2025 11:08AM

Rejection Time (UTC): 02/11/2025 11:08AM

Fail Error: Reason: [{LED=550 4.4.7

QUEUE.Expired; message expired};{MSG=};{FQDN=};{IP=};{LRT=}]

Answer 1

Hi @John Peter ,

Welcome to the Microsoft Q&A platform!

4.4.7 is usually a send connector configuration problem. Consider checking the send connector configuration in the following ways:

1. Use nslookup to verify that the target domain can be accessed from the Exchange server.
2. The FQDN provided by the sending connector to the HELO or EHLO request does not match the hostname in the MX record.

For 4.4.7 errors you can refer to:https://learn.microsoft.com/en-us/exchange/mail-flow/non-delivery-reports-and-bounce-messages/non-delivery-reports-and-bounce-messages?view=exchserver-2019#temporary-delivery-failures

If the send connector is configured correctly, consider whether the domain is configured correctly:

1. The Sender Policy Framework (SPF) record for your domain may be incomplete and may not include all email sources for your domain.
2. Your domain may have expired due to non-payment. Verify with your domain registrar that your domain is active and not expired.
3. If the recipient is located in a local Exchange organization in a hybrid deployment, there may be an issue with your hybrid configuration. Provide the information in the NDR to the local Exchange administrator.
   For more you can refer to:https://learn.microsoft.com/en-us/exchange/troubleshoot/email-delivery/ndr/fix-error-code-550-4-4-7-in-exchange-online#im-an-email-admin-how-do-i-fix-this

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