Deskpro uses a variety of techniques to determine if an incoming Email message is a reply to an existing Ticket.

One method used is to compare the subject line of an incoming message with the User’s existing Tickets.

By default, Deskpro only does subject matching for messages when the subject line is prefixed with RE:, which normally indicates that the User was replying.

In some situations, you may want to apply subject line matching to messages without the RE: prefix (for example, if you want to accept Tickets from automated systems that don’t add the RE: like eBay).

To do this, select Enable subject matching on all email messages checkbox in Channels > Emails > Settings.

By default, Deskpro applies subject matching across all your Email accounts. For example, if the User sends two Emails with the same subject to both “sales@example.com” and “support@example.com”, their second one may be matched into the same Ticket.

You may want to restrict subject matching so it only applies to messages sent to the same account. In this case, tick the 'Only match subjects on the same email account' checkbox.

You can also enable Ignore participants when matching subjects for all emails. This would mean that if two Users sent in Emails with the same subject, they would get threaded and added onto one single Ticket. This setting may be useful in cases where you are forwarding Tickets out of your helpdesk to other Users not on the original Ticket, but want the forwardee to be able to reply and have that response be added onto the original Ticket.