How to know the reason of eventIID in messagetracklog is fail and the source is routing

Question

When the external mailbox was sent to the organization's Exchange users, the users reported that they did not receive the email. However, I checked on the anti-spam gateway and found that the email had been delivered to the mail server. Then I checked the message tracking log and found that the email delivery failed. Check the status is 'RecipientStatus : {[{LED=550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup};{MSG=};{FQDN=};{IP=};{LRT=}]}'   but I can send email to this group normally

Answer 1

Hi @姚黎忠,

According to your description, there is only one external user have the issue to send message to your group, so we could know that the configuration of the group should be correct. I suggest you follow these steps to troubleshoot:

1. Try asking the other users who are from the same organization with this specific user to send emails to the group, and check if the issue persist. This can help isolate whether this issue is related to the whole domain or single user.

2.Check if there are any mail flow rules that may affect or block messages from specific senders or domains. In the Exchange admin center, go to Mail Flow > Rules.

3. Try to ask the specific user to send the message using the email address directly instead of any autocomplete or cache info.