How to resolve this error "Email contains the same Message-ID as a previous sent email..." in PRB

[apoorvaagar]

Hi All,

One of my instances, have been upgraded to Australia release and I am trying to send an email for a Particular Problem ticket,  the email is being received within servicenow but is not being added in the work notes of Problem record. Below is the error I can see in email logs:

"Email contains the same Message-ID as a previous sent email, preventing loop by setting it to 'Ignored' state"

I have checked in email table, the message-id doesn't have any duplicate records.

Please help me in fixing this error.

Thanks.

[Dr Atul G- LNG]

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0816001

[meri45clark]

Hi,

This error is caused by ServiceNow’s email loop prevention, not by duplicate entries in sys_email.

The message:

“Email contains the same Message-ID as a previous sent email, preventing loop”

means ServiceNow has already processed this email’s Message-ID earlier, so it is marking it as Ignored to avoid reprocessing the same email again.

Likely causes:

• Email is being forwarded/redirected (not freshly sent)
• Mail server is re-sending the same message with the same Message-ID
• A forwarding rule or integration is replaying the email
• Post-upgrade (Australia release), stricter loop detection is now applied

What you can do:

• Check if the email is being forwarded instead of newly generated
• Verify mail routing rules in your email system (O365/Gmail/etc.)
• Search sys_email using headers for the same Message-ID (it may exist in processed/ignored records)
• Try sending a brand new email (not forwarded) to confirm behavior

[Tanushree Maiti]

Hi @apoorvaagar 

Refer Article: emails get received-ignored in servicenow

refer KB : 

KB0790932 How to resolve email notifications marked as send-ignored 

KB0535129 How to troubleshoot email notification errors 

KB0816001 How emails with duplicate Message ID's are handled in ServiceNow