When comparing sales report data you may occasionally find that the Portal based reports show lower amounts than the Register Application. The most likely cause for this is that the device is no longer connected to the internet – so any sales made during this time are still saved locally on the device and not uploaded to the server. To get the device back online please see the FAQ – Cannot Update Data or Sync Device.
Once the network connection has been restored on the device, perform an Update Data from the login screen. This will push any locally stored transactions up to the server.