A Data Source may receive an ItemSyncResponse, if applicable. Currently, ItemSyncResponses are generated and sent only if errors occur during item synchronization. After an item has been published and subscribed to by a data recipient, if the data fails at 1SYNC due to incorrect/insufficient data for the published GTINs and their hierarchies or fails Recipient Data Pool CIN validations, an Item Sync Response is generated and sent to the publisher (data source). An entry is also sent to the Data Source's Worklist.