We have a system which emails OTRS when it has issues with jobs, so for example in the body we will have "Transaction ID: xxxxx", I have OTRS saving these values in TicketKey and TicketValue. However, each time an email referencing ID: xxxxx is received it makes a new ticket

What am I doing wrong, or can't OTRS match on this?
Please bear in mind that OTRS does everything else we require for the rest of the business!
Thanks in advance.