This happens when, during the synchronization of a product previously sent by the module to Ebay successfully, an advertisement that no longer exists Ebay is detected. This can happen when references of obsolete advertisements remain in the form or when “forced” advertisements are closed against Ebay violations. In order to re-send a product that is in this condition it is necessary to remove the association that the module maintains between Prestashop ID and Ebay ID. The operation can be performed through a Fast synchronization (during the download of the reply the invalid references will be eliminated) or by temporarily deactivating the product involved and launching a synchronization in “Product closure” mode.