Export to Excel on IE11 Browser

HttpContext.Current.Response.ClearContent();
                HttpContext.Current.Response.Clear();
                HttpContext.Current.Response.Buffer = true;
               // HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";
                HttpContext.Current.Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml";
                HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=ExportGridviewData.xlsx");
                HttpContext.Current.Response.Charset = "";

                MemoryStream ms = new MemoryStream();

                using (var excelSpreadSheet = SpreadsheetDocument.Create(ms, DocumentFormat.OpenXml.SpreadsheetDocumentType.Workbook))
                {
                    var excelworkbookPart = excelSpreadSheet.AddWorkbookPart();
                    excelSpreadSheet.WorkbookPart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();
                    excelSpreadSheet.WorkbookPart.Workbook.Sheets = new DocumentFormat.OpenXml.Spreadsheet.Sheets();

                    //Add a stylesheet to support the formatting
                    // Stylesheet
                    DocumentFormat.OpenXml.Packaging.WorkbookStylesPart workbookStylesPart;

                    workbookStylesPart = excelSpreadSheet.WorkbookPart.AddNewPart<DocumentFormat.OpenXml.Packaging.WorkbookStylesPart>();
                    workbookStylesPart.Stylesheet = new DocumentFormat.OpenXml.Spreadsheet.Stylesheet();
                    workbookStylesPart.Stylesheet.Save();

                    AddBasicStyles(excelSpreadSheet);

                    uint sheetId = 1;

                    foreach (System.Data.DataTable dataTable in pExportedDataSet.Tables)
                    {
                        var sheetPart = excelSpreadSheet.WorkbookPart.AddNewPart<WorksheetPart>();
                        var sheetData = new DocumentFormat.OpenXml.Spreadsheet.SheetData();
                        sheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(sheetData);

                        DocumentFormat.OpenXml.Spreadsheet.Sheets excelSheets = excelSpreadSheet.WorkbookPart.Workbook.GetFirstChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>();
                        string relationshipId = excelSpreadSheet.WorkbookPart.GetIdOfPart(sheetPart);

                        if (excelSheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Count() > 0)
                        {
                            sheetId = excelSheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Select(s => s.SheetId.Value).Max() + 1;
                        }

                        DocumentFormat.OpenXml.Spreadsheet.Sheet excelsheet = new DocumentFormat.OpenXml.Spreadsheet.Sheet() { Id = relationshipId, SheetId = sheetId, Name = dataTable.TableName };
                        excelSheets.Append(excelsheet);

                        DocumentFormat.OpenXml.Spreadsheet.Row headerRow = new DocumentFormat.OpenXml.Spreadsheet.Row();

                        List<String> dspColumns = new List<string>();
                        foreach (DataColumn HZLstcolumn in dataTable.Columns)
                        {
                            dspColumns.Add(HZLstcolumn.ColumnName);

                            DocumentFormat.OpenXml.Spreadsheet.Cell exlcell = new DocumentFormat.OpenXml.Spreadsheet.Cell();

                            //Headers are strings
                            exlcell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;

                            //Write out the string
                            exlcell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(HZLstcolumn.ColumnName);
                            headerRow.AppendChild(exlcell);

                        }

                        sheetData.AppendChild(headerRow);
                        foreach (DataRow exlDataRow in dataTable.Rows)
                        {
                            DocumentFormat.OpenXml.Spreadsheet.Row newRow = new DocumentFormat.OpenXml.Spreadsheet.Row();
                            foreach (String HZExlcol in dspColumns)
                            {
                                DocumentFormat.OpenXml.Spreadsheet.Cell rowCell = new DocumentFormat.OpenXml.Spreadsheet.Cell();


                                rowCell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                                rowCell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(exlDataRow[HZExlcol].ToString());


newRow.AppendChild(rowCell);
            }
            sheetData.AppendChild(newRow);

        }

        //added for Merge

        //end added for meger

    }
}

ms.WriteTo(HttpContext.Current.Response.OutputStream);

//HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();
HttpContext.Current.Response.Close();
System.Web.HttpContext.Current.ApplicationInstance.CompleteRequest();