Why can't checked first row in datagridview C# the results of my code all data except the first row ?

datagridview loaded only one data then i clicked SelectALL but row not selected

What I have tried:

private void ReportViewer_Load(object sender, EventArgs e)
        {
    grdEmailData.ColumnHeaderMouseClick += grdEmailData_ColumnHeaderMouseClick;
       
 }

private void btnSearch_Click(object sender, EventArgs e)
        {
            try
            {
                using (SqlConnection connection = new SqlConnection(ConnectionString))
                {
                    connection.Open();

                    string query = "SELECT * FROM email_notification WHERE bank_code = @BankCode AND stmdate = @StmDate " +
                                   "UNION " +
                                   "SELECT * FROM email_notification_arc WHERE bank_code = @BankCode AND stmdate = @StmDate";

                    using (SqlCommand command = new SqlCommand(query, connection))
                    {
                        command.Parameters.AddWithValue("@BankCode", _fiid); // Assuming _serverName is the bank code
                        command.Parameters.AddWithValue("@StmDate", dtpStmDate.Value.ToString("dd/MM/yyyy")); 

                        SqlDataAdapter adapter = new SqlDataAdapter(command);
                        DataTable dataTable = new DataTable();
                        adapter.Fill(dataTable);


                        DataGridViewCheckBoxColumn checkBoxColumn = new DataGridViewCheckBoxColumn();
                        checkBoxColumn.HeaderText = "SelectALL";
                        checkBoxColumn.Name = "All";
                        grdEmailData.Columns.Insert(0, checkBoxColumn);


                        // Bind the data to the DataGridView
                        grdEmailData.DataSource = dataTable;

                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show($"Error loading data: {ex.Message}", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

 private void grdEmailData_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            // Check if the clicked cell is in the "All" column header
            if (e.RowIndex == -1 && e.ColumnIndex == grdEmailData.Columns["All"].Index)
            {
                ToggleSelectAll();
            }
        }


        private void ToggleSelectAll()
        {
            // Toggle the select/unselect all logic in the "All" column
            bool selectAll = true;

            foreach (DataGridViewRow row in grdEmailData.Rows)
            {
                
                DataGridViewCheckBoxCell checkBoxCell = row.Cells["All"] as DataGridViewCheckBoxCell;

                if (checkBoxCell != null)
                {
                    checkBoxCell.Value = selectAll;
                }
            }
        }