Corrupt xlsx file when uploading via Java FTP

I'm trying to upload a file via FTP, the excel file apparently is copying it correctly, but when I open it, it says it's corrupt.

Any ideas ??

public static void enviarArchivoFTP(String localFile, String hostFile) throws FileNotFoundException, IOException{
    //fis = new FileInputStream(localFile);
    BufferedInputStream buffIn = new BufferedInputStream(new FileInputStream(localFile));
    ftp.setFileType(FTP.BINARY_FILE_TYPE);
    ftp.enterLocalPassiveMode();

    if(ftp.storeFile(hostFile,buffIn))
        System.out.println("Envio correcto");
    else
        System.out.println("Error Envio");
    //fis.close();
    buffIn.close();
}