Check these in order: (1) the list shows one month by creation date — use the month arrows or date picker at the top; (2) if a kitchen location is selected, only that location's orders appear — switch location or view all locations; (3) column filters may be active on the Date, User, Type or Status columns — clear them; (4) the customer may have an abandoned cart rather than a placed order — check Reports > Abandoned Carts; (5) for card payments still awaiting bank authentication, the order does exist with status Pending Authentication. The built-in search box also works, but only searches within the month currently loaded.