JSM Email Threading Failing

[Owain_Esau]

Hi,

I'm experiencing inconsistent email threading issues when communicating with vendors who use ManageEngine ServiceDesk Plus as their ticketing system. Here's the situation:

Our setup works as follows:

• We have an automation rule that successfully adds the vendor's ticket number to our JSM ticket subject line
• Another automation rule adds vendors as participants and sends them an email, which threads correctly into ManageEngine
• However, when vendors reply (with the JSM ticket number and project key in the subject), it creates a new ticket in our system about 50% of the time instead of threading to the existing ticket

I've verified that the message headers in the failed replies show matching reply IDs to the original ticket, so the threading information appears to be present. Has anyone encountered similar intermittent threading issues with ManageEngine ServiceDesk Plus, or have suggestions for troubleshooting this inconsistent behaviour?