The search bar results will only show reservations that their check-out date was in the past 6 months. If you require the ability to search for older reservations, contact us or your Customer Success Manager.
If you think the reservation exists, but it's not coming up in the search results, we recommend creating a reservation report and looking for it there. To pull up reservations that are more than 6 months old, you can add the "Check Out" filter to the reservation report. From the dropdown, select "Is before the last" and type "180" next to the "Days" textbox.