"End of Central Directory record could not be found" Random Error during CreateReader

[mikegit75]

I'm getting this random error
System.IO.InvalidDataException: End of Central Directory record could not be found. at System.IO.Compression.ZipArchive.ReadEndOfCentralDirectory() at System.IO.Compression.ZipArchive..ctor(Stream stream, ZipArchiveMode mode, Boolean leaveOpen, Encoding entryNameEncoding) at ExcelDataReader.Core.ZipWorker..ctor(Stream fileStream) at ExcelDataReader.ExcelOpenXmlReader..ctor(Stream stream) at ExcelDataReader.ExcelReaderFactory.CreateReader(Stream fileStream, ExcelReaderConfiguration configuration)

Below is part of the code where the error happens:
` Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

        Stream stream = await GetFTPFile(_ftp_UrlAndFilename, _ftp_username, _ftp_password);

        try
        {
            using var reader = ExcelReaderFactory.CreateReader(stream);

            DataSet ds = reader.AsDataSet(new ExcelDataSetConfiguration()
            {
                ConfigureDataTable = (tableReader) => new ExcelDataTableConfiguration()
                {
                    UseHeaderRow = true
                }
            });

            foreach (DataColumn column in ds.Tables[0].Columns)
            {
                if (column.ColumnName.Contains(""))
                    column.ColumnName = column.ColumnName.Replace(" ", "");
            }

            return ds.Tables[0].ToList<SellerCloudInventory>();
        }
        catch (Exception ex)
        {
            throw new Exception($"There was a problem converting the inventory file from an excel file. The stream length was {stream.Length}.", ex);
        }`

I'm pretty sure that the file we're reading is xlsx file. The error sometimes happens and sometimes don't.
Any help please? :) Thanks!

[appel1]

My guess would be that either the files are trunkated on the FTP source or not the whole file gets downloaded.

Does it happen if you download it to a local file first and then try to open it?