Tickets & Conversations


Tickets not merged (duplication of the same conversation)

Hello community,


I've encountered a new issue that has rendered the tracking of service tickets unusable.


When we receive a new email in our inbox, a new service ticket is correctly created. However, when we reply to this ticket using our inbox email address and add our email address in Bcc, a new conversation is created in our HubSpot spam box instead of updating the existing ticket. After marking this conversation as not spam, a new ticket is created instead of updating the existing one. Please note that when we reply to the original email, we also update the subject of that mail. We add between brackets the Hubspot ticket number as a prefix of the original email subject.


We have been following this process for several months without issues, but recently, this problem has arisen.


Does anyone have any idea why the tracking of existing tickets is not working? This issue is quite problematic for our organization's service team.


Thank you,

3 Replies 3
Not applicable

Tickets not merged (duplication of the same conversation)

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Tickets not merged (duplication of the same conversation)



I've checked all the mentioned parameters using the Email Header Analyzer tool. For instance, the IN_REPLY_TO parameter of our reply email is set up with the correct message ID of the original email received in the inbox, which is:


Furthermore, I can confirm that we have already added our own email domain to the allow list. However, all reply emails sent from our inbox continue to fall into the spam box. So we have no other choice but going to Conversations to manually mark our reply emails as no spam. But when doing so, a new ticket ID is created instead of updating the initial one, which makes the tracking of all exchanges unusable.


Let me reiterate that we have been following this process for months without encountering this issue. We have not made any changes to our Outlook or domain settings. There appears to be a regression originating from HubSpot that we cannot explain, suddenly disrupting our customer support workflow.


Thank you for your assistance.



Community Manager
Community Manager

Tickets not merged (duplication of the same conversation)

Hi @CedricI,


Thanks for reaching out to the Community! 


I wanted to share some information on how emails are threaded in HubSpot.

IN_REPLY_TO: If the email header of the email contains an IN_REPLY_TO parameter, HubSpot will thread it because there was an inReplyToMessageId header that referenced an existing email on this thread.

REFERENCES_CHAIN: If the email header contains this parameter, HubSpot knows that there was a matching messageId in the References header of this particular email that tied this email to a pre-existing thread.

SUBJECT: Occasionally HubSpot uses subject-based threading. HubSpot only does subject-based indexing/threading when there is neither an inReplyTo header nor a References header. We will match the subject line of the email with a previous email that also contains the same email addresses. This strategy is less common.

If the email received does not contain any of these parameters, HubSpot is unable to match the incoming email with an existing conversation. As a result, a new conversation ticket is created.  


I would recommend using this Email Header Analyzer tool to see if the emails are following under the above parameters. If the parameters don't appear in the email header, the expected behavior would be for HubSpot to create a new ticket. 


I also wanted to ask a few clarifying questions regarding spam: 
1)  Are you noticing that all emails you receive in the conversations inbox are being marked as spam or only a few emails? 
2)  Can you verify if you have any email domains or role-based emails on your allow and deny list by checking your list against this knowledge base article?  

Thank you! 




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