Watermark Collision with existing record

[RuchithaP]

Summary of Issue:
Inbound emails from particular servicenow instance are failing to trigger our 'New' Inbound Action because they are being logged as 'Received Ignored'.

Technical Root Cause:
The incoming email body contains a ServiceNow watermark (Ref:MSGxxxxxxx). Because of this watermark, the email engine automatically classifies the email Type as 'Reply' instead of 'New'. Since it matches an existing record in Email Watermarks(sys_watermark) table in our instance, it skips our 'New' Inbound Action rules entirely and gets ignored and target record is not being created.

Requested Assistance:
We need this inbound email to execute our 'New' Inbound Action logic to create a ticket automatically. Please advise on the best platform practice to prevent this specific sender's email from being locked into a 'Reply' classification based on the watermark.

• Testing Performed: We verified this behaviour in our development instance by temporarily deleting the conflicting watermark record. Once removed, the incoming email was successfully classified as New and processed correctly. (example: MSG1216286)
• Constraint: Deleting or modifying existing production watermarks is not a viable or safe option.

What is the recommended best practice or workaround to prevent a specific sender's email from being locked into a Reply classification based on an external watermark collision?

[GlideFather]

ahoy @RuchithaP,

could you possibly explain the use case? Your ServiceNow instance receives an email with a watermark and doesn't create a new incident due to that? How did the watermark got into that email body then?

[RuchithaP]

Hello @GlideFather 

We are setting up an instance-to-instance communication via inbound actions where we configured an inbound action named create email. Another ServiceNow instance (belonging to our vendor/external partner) is automatically sending emails to our instance to trigger email ticket creation on our side.

How the Watermark Got There

Because the sending system is also a ServiceNow instance, its email engine automatically appends its own watermark (Ref:MSGxxxxxxx) to the bottom of the email body upon generation.

When that email hits our instance, our email engine scans the body, detects the Ref:MSG string, and checks our local sys_watermark table. Due to a random string collision, the external instance's watermark happens to match an existing watermark record in our system. As a result, our platform incorrectly classifies the incoming email as a Reply instead of New, skipping our creation logic and marking the email as Received Ignored.

Since we cannot control the outgoing email format of the external instance or safely delete our own production watermarks, we are looking for the best platform practice to bypass or override this classification for this specific sender.

[GlideFather]

@RuchithaP understand it now, thanks.

Maybe you can focus on the format/convention of the vendor's watermark and apply it to a newly created inbound action that would reflect this pattern...

Something like this (dummy example), Conditions or From (if you receive it from the same email/instance) as seen below:

[RuchithaP]

@GlideFather Thank you for the quick response

Based on my understanding, the email will be classified as reply before reaching to inbound action. Then vendor's watermark convention might not be useful. Could you suggest on this

1.) Email arrives → engine scans for watermark
2.) Watermark found → matched against sys_email_watermark table
3.) Email classified as Reply → routed to existing record
4.) New inbound action rules → never evaluated