Stub example working with EPPlus and MailKit

stub.cs

foreach (DataRow task in tasks)
{
    DataRow manufacturer = GetManufacturer(Convert.ToInt32(task["ManufacturerID"]));
    DataRowCollection recipients = GetRecipients(Convert.ToInt32(task["ManufacturerID"]));

    if (recipients.Count > 0)
    {
        DataSet results = GetResults(Convert.ToDateTime(task["StartDate"]), Convert.ToDateTime(task["EndDate"]), Convert.ToInt32(task["ManufacturerID"]));
        ExcelPackage package = new ExcelPackage();
        ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Sheet1");
        worksheet.Cells["A1"].LoadFromDataTable(results.Tables[0], true);
        worksheet.Column(5).Style.Numberformat.Format = "#0%";
        worksheet.Column(7).Style.Numberformat.Format = "#0%";
        worksheet.Column(9).Style.Numberformat.Format = "#0%";
        worksheet.Cells[worksheet.Dimension.Address].AutoFilter = true;
        worksheet.Cells[worksheet.Dimension.Address].AutoFitColumns();
        byte[] workbook = package.GetAsByteArray();
        MemoryStream stream = new MemoryStream(workbook);
        DataRowCollection sitesExcludedRows = results.Tables[1].Rows;
        List<string> sitesExcluded = new List<string>();

        foreach (DataRow site in sitesExcludedRows)
        {
            sitesExcluded.Add(site["Name"].ToString());
        }

        MimePart attachment = new MimePart("application", "vnd.openxmlformats-officedocument.spreadsheetml.sheet")
        {
            Content = new MimeContent(stream, ContentEncoding.Default),
            ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
            ContentTransferEncoding = ContentEncoding.Base64,
            FileName = "Summary.xlsx"
        };

        MimeMessage message = new MimeMessage();
        message.From.Add(new MailboxAddress(appSettings["EmailFromName"], appSettings["EmailFromAddress"]));

        foreach (DataRow recipient in recipients)
        {
            message.Bcc.Add(new MailboxAddress(recipient["EmailAddress"].ToString()));
        }

        message.Subject = $"{manufacturer["Name"].ToString()} Weekly Summary";
        string html = template.Render(new
        {
            Title = $"{manufacturer["Name"].ToString()} Weekly Summary",
            ImageUrl = $"{manufacturer["LogoPath"].ToString()}",
            StartDate = Convert.ToDateTime(task["StartDate"]),
            EndDate = Convert.ToDateTime(task["EndDate"]),
            SitesExcluded = sitesExcluded.Count > 0 ? sitesExcluded : null
        });
        TextPart plainBody = new TextPart("plain")
        {
            Text = ReadSharp.HtmlUtilities.ConvertToPlainText(html)
        };
        TextPart htmlBody = new TextPart("html")
        {
            Text = html
        };
        Multipart alternative = new Multipart("alternative")
        {
            plainBody,
            htmlBody
        };
        Multipart multipart = new Multipart("mixed")
        {
            alternative,
            attachment
        };
        message.Body = multipart;

        try
        {
            using (SmtpClient client = new SmtpClient())
            {
                client.Connect(appSettings["SMTPHost"], int.Parse(appSettings["SMTPPort"]));
                client.Authenticate(appSettings["SMTPUser"], appSettings["SMTPPass"]);
                client.Send(message);
                client.Disconnect(true);
            }
        }

        catch (Exception error)
        {
            log.Fatal("Unable to send email.", error);
            Environment.Exit((int)ExitCode.SmtpError);
        }
    }
}

excellent example
Thank you