I wrote a program that connects to MS Access. When I fill in the fields and add a new item to Access the program fails. The exception is "Syntax error in INSERT INTO statement"

Here is the relevant code.

****************************************************************
AdoHelper.cs
****************************************************************

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.OleDb;

namespace Yad2
{
    class AdoHelper
    {
        //get the connection string from the app.config file
        //Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Yad2.accdb
        static string connectionString = Properties.Settings.Default.DBConnection.ToString();

        //declare the db connection
        static OleDbConnection con = new OleDbConnection(connectionString);

        /// <summary>
        /// To Execute queries which returns result set (table / relation)
        /// </summary>
        /// <param name="query">the query string</param>
        /// <returns></returns>
        public static DataTable ExecuteDataTable(string query)
        {

            try
            {
                con.Open();
                OleDbCommand command = new OleDbCommand(query, con);
                System.Data.OleDb.OleDbDataAdapter tableAdapter = new System.Data.OleDb.OleDbDataAdapter(command);
                DataTable dt = new DataTable();
                tableAdapter.Fill(dt);
                return dt;
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            con.Close();
        }
    }

    /// <summary>
    /// To Execute update / insert / delete queries
    /// </summary>
    /// <param name="query">the query string</param>
    public static void ExecuteNonQuery(string query)
    {
        try
        {
            con.Open();
            System.Data.OleDb.OleDbCommand command = new System.Data.OleDb.OleDbCommand(query, con);
            command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            con.Close();
        }
    }

    /// <summary>
    /// To Execute queries which return scalar value
    /// </summary>
    /// <param name="query">the query string</param>
    public static object ExecuteScalar(string query)
    {
        try
        {
            con.Open();
            System.Data.OleDb.OleDbCommand command = new System.Data.OleDb.OleDbCommand(query, con);  /// here is the Excaption !!!!!!!!!
            return command.ExecuteScalar();
        }
        catch
        {
            throw;
        }
        finally
        {
            con.Close();
        }
    }

}
}

****************************************************************************


****************************************************************************
DataQueries.cs
****************************************************************************
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;

namespace Yad2
{
    class DataQueries
    {

        public static DataTable GetAllItems()
        {
            try
            {
                string query = "Select * from Messages";

                DataTable dt = AdoHelper.ExecuteDataTable(query);

                return dt;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }


        public static void AddNewItem(string mesNumber, string title , string mesDate , string contactMail , string mesType , string Details )
        {
            string query = "Insert into Messages values(" + mesNumber + " , '" + title + "' , '" + mesDate + "' , '" + contactMail + "' , , '" + mesType + "' , '" + Details + "')";
            AdoHelper.ExecuteNonQuery(query);
       }

        public static void DeleteDept(int mesNumber)
        {
            string query = "Delete from Item where MessageNumber=" + mesNumber;
            AdoHelper.ExecuteNonQuery(query);
        }
    }
}
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plase help me .... why the program falls ?