Maui App keep crashing when exporting excel file on iOs

Question

My app was working fine until I added the ability to export data as xsls file. The app crashes immediately when exporting the file. I used FolderPicker to get the path from user and then combine it with the file name. I m using closedXmL.Excel library to construct the excel file from a data table then use workbook.saveas() to save it to the path provided.

The app works fine on simulators on visual studio mac. But crashes on a real iPhone 13

here is the part of my code that deals with this:

 [RelayCommand]
 async Task Export()
 {
     try
     {
         DataTable dt = new DataTable();
         dt.Columns.Add("Day");
         dt.Columns.Add("Inc");
         dt.Columns.Add("Exp");
         dt.Columns.Add("Tip");
         dt.Columns.Add("Net");
         dt.Columns.Add("Wrks");

         foreach (SqlRecord s in SelectedMonthRecords)
         {
             DataRow dr = dt.NewRow();
             dr[0] = s.Date;
             dr[1] = Convert.ToDouble(s.Income);
             dr[2] = Convert.ToDouble(s.DailyExp);
             dr[3] = Convert.ToDouble(s.Tip);
             dr[4] = Convert.ToDouble(s.DailyNet);
             dr[5] = Convert.ToDouble(s.Workers);
             dt.Rows.Add(dr);
         }

         dt.AcceptChanges();

         string filename = (DateTime.Now.Year.ToString() +
             DateTime.Now.Month.ToString() + DateTime.Now.Day.ToString() +
             DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString());

         XLWorkbook wb = new XLWorkbook();

         var ws = wb.Worksheets.Add(dt, "Sheet 1");

         CancellationToken ct = new CancellationToken();
         var Pth = await PickFolderAsync(ct);
         filename = filename + ".xlsx";
         var path = Path.Combine(Pth, filename);
         wb.SaveAs(path);
     }
     catch (Exception e)
     {

         throw;
     }

     async Task<string> PickFolderAsync(CancellationToken cancellationToken)
     {
         var result = await FolderPicker.Default.PickAsync(cancellationToken);
         if (result.IsSuccessful)
         {
             //await Toast.Make($"The folder was picked: Name - {result.Folder.Name}, Path - {result.Folder.Path}", ToastDuration.Long).Show(cancellationToken);
         }
         else
         {
             //await Toast.Make($"The folder was not picked with error: {result.Exception.Message}").Show(cancellationToken);
         }
         return result.Folder.Path;
     }

 }

I m not sure if it relates to permissions on iOs but i have read in apple documentation that there is no need for permissions for file storing on iOs (unlike android).