We found a problem with some content in "example.xlsx" - using ClosedXML library - asp.net

Question

I'm using ClosedXML library to generate a simple Excel file with 2 worksheets.
I keep getting error message whenever i try to open the file saying
"We found a problem with some content in "example.xlsx". Do you want us to try to recover as much as we can. if you trust source of this workbook, click Yes"
If i click Yes, it displays the data as expected, i don't see any
problems with it. Also if i generate only 1 worksheet this error does
not appear.
This is what my stored procedure returns, first result set is populated in sheet1 and second result set is populated in sheet2, which works as expected.
Workbook data
Here is the method i am using, it returns 2 result sets and populates both result sets in 2 different worksheets:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult POAReport(POAReportVM model)
{
POAReportVM poaReportVM = reportService.GetPOAReport(model);
using (var workbook = new XLWorkbook())
{
IXLWorksheet worksheet1 = workbook.Worksheets.Add("ProductOrderAccuracy");
worksheet1.Cell("A1").Value = "DATE";
worksheet1.Cell("B1").Value = "ORDER";
worksheet1.Cell("C1").Value = "";
var countsheet1 = 2;
for (int i = 0; i < poaReportVM.productOrderAccuracyList.Count; i++)
{
worksheet1.Cell(countsheet1, 1).Value = poaReportVM.productOrderAccuracyList[i].CompletedDate.ToString();
worksheet1.Cell(countsheet1, 2).Value = poaReportVM.productOrderAccuracyList[i].WebOrderID.ToString();
worksheet1.Cell(countsheet1, 3).Value = poaReportVM.productOrderAccuracyList[i].CompletedIndicator;
countsheet1++;
}
IXLWorksheet worksheet2 = workbook.Worksheets.Add("Summary");
worksheet2.Cell("A1").Value = "Total Orders Sampled";
worksheet2.Cell("B1").Value = "Passed";
worksheet2.Cell("C1").Value = "% Passed";
worksheet2.Cell(2, 1).Value = poaReportVM.summaryVM.TotalOrdersSampled.ToString();
worksheet2.Cell(2, 2).Value = poaReportVM.summaryVM.Passed.ToString();
worksheet2.Cell(2, 3).Value = poaReportVM.summaryVM.PassedPercentage.ToString();
//save file to memory stream and return it as byte array
using (var ms = new MemoryStream())
{
workbook.SaveAs(ms);
ms.Position = 0;
var content = ms.ToArray();
return File(content, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
}
}
}

Answer 1

I had similar problem. For me the cause was as mentioned in this answer:
I had this issue when I was using EPPlus to customise an existing template. For me the issue was in the template itself as it contained invalid references to lookup tables. I found this in Formula -> Name Manager.
You may find other solutions there.
Apologies as my reputation is too low to add a comment.