An SFTP server is a temporary exchange place. For security and space management reasons, exchanged files are regularly deleted.
First of all, the files uploaded by the merchant to the SFTP server or generated by the payment gateway are automatically compressed 7 days after their upload date. The .gz extension is added to the filename.
Furthermore, all files are deleted 21 days after they were uploaded by the merchant or generated by the gateway. This removal will always be initiated by the payment gateway.