While executing my code I get exception

Question

I have implemented my work, but it is throwing exceptions- Exception from HRESULT: 0x800A03EC. It comes in the "for" loop. I have to extract the rows(A-H) where character "d" is present. Suppose if "d" is present in column "M" at "M6" cell, then I need to extract A6-H6 and send it via outlook mail. 

Please help me!

This is what I have done so far :

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Excel = Microsoft.Office.Interop.Excel;
using Outlook = Microsoft.Office.Interop.Outlook;

using System.Collections;

namespace XYZ
{
class Program
{
//method to send email to outlook
public static void sendEMailThroughOUTLOOK()
{
try
{
// Create the Outlook application.
Outlook.Application oApp = new Outlook.Application();

// Create a new mail item.
Outlook.MailItem oMsg =
(Outlook.MailItem)oApp.CreateItem(Outlook.OlItemType.olMailItem);

// Set HTMLBody.
//add the body of the email
oMsg.HTMLBody = "See the details";

//Subject line oMsg.Subject = "Doc Info";

// Add a recipient.
Outlook.Recipients oRecips = (Outlook.Recipients)oMsg.Recipients;

// Change the recipient in the next line if necessary.
Outlook.Recipient oRecip = (Outlook.Recipient)oRecips.Add("[email protected]"), oRecip.Resolve();

// Send.
oMsg.Send();

// Clean up.
oRecip = null;
oRecips = null;
oMsg = null;
oApp = null;
}
catch (Exception ex)
{
}
}

private static string EX_PATH = @"F:\Document_Excel.xlsm";
private static Excel.Workbook AXBook = null;
private static Excel.Application AXApp = null;
private static Excel.Worksheet AXSheet = null;

public static string exception = "";

static void Main(string[] args)
{
if (args == null || args.Length < 4)
{
Console.WriteLine("Let's start the work!");
Console.WriteLine("press any key to continue");
Console.ReadLine();
}
else
{
AX_PATH = args[0];
}

AXApp = new Excel.Application();
AXApp.Visible = true;

exception = "";
try
{
AXBook = AXApp.Workbooks.Open(AX_PATH, 0, true, 5, "", "", true,Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
}
catch (System.Exception ex)
{
exception = ex.Message;
}

exception = "";
try
{
AXSheet = (Excel.Worksheet)AXBook.Sheets["Sheet First"];
}
catch (Exception ex)
{
exception = ex.Message;
}

Console.WriteLine("Hello");

Excel.Range last = AXSheet.Cells.SpecialCells(Excel.XlCellType.xlCellTypeLastCell, Type.Missing);
Excel.Range range = AXSheet.get_Range("A1", last);
int lastUsedRow = last.Row;
int lastUsedColumn = last.Column;

Object missing = System.Type.Missing;
for (int i = AXSheet.Cells.get_Range("d", missing).Row + 1; i <= last.Row; i++)
{

Console.WriteLine("Hello");
sendEMailThroughOUTLOOK();
}

}
}

}