Some emails to my ticket email accounts are sent via eBay. Deskpro sometimes creates a new ticket for reply emails, when it should be linking them to an existing ticket.
eBay strips out some of the usual cues that Deskpro uses to detect that emails are responses to an existing ticket, such as prefixing replies with "RE:".
To fix this issue, go to Admin > Tickets > Email Accounts, and click Advanced Settings at the lower left.
Check the Enable subject matching on ALL email messages option, then click Save.
This option can also be useful if Deskpro is having problems correctly matching emails from other automated systems.