Ошибка при занесении данных в базу

Пытаюсь реализовать форму регистрации для БД. После запуска Winform выдает ошибку.

Файл Program.cs

 class  DB
    {
        SqlConnection connection = new SqlConnection(@"Data Source=(local);Initial Catalog=Cursac;Integrated Security=True");
        public void OpenSQL()
        {
            if(connection.State== System.Data.ConnectionState.Closed)
            {
                connection.Open();
            }
        }
        public void ClodeSQL()
        {
            if (connection.State == System.Data.ConnectionState.Open)
            {
                connection.Close();
            }
        }
        public SqlConnection connectionSQL()
        {
            return connection;
        }
    }

Файл Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Cursach
{
    public partial class Form1 : Form
    {
        Point FormPoint;
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }
        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {
            if (textBox2.UseSystemPasswordChar == true)
            {
                textBox2.UseSystemPasswordChar = false;
            }else { textBox2.UseSystemPasswordChar = true; }
        }
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if(e.Button==MouseButtons.Left)
            {
                this.Left += e.X - FormPoint.X;
                this.Top += e.Y - FormPoint.Y;
            }
        }
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            FormPoint = new Point(e.X, e.Y);
        }
        private void button2_Click(object sender, EventArgs e)
        {
            DB db = new DB();
            SqlCommand command = new SqlCommand("INSERT INTO `Login_Pass` (`Login`, `pass`) VALUES (@rL, @rP)", db.ConnectionSQL());
            command.Parameters.Add("@rL",SqlDbType.VarChar).Value = textBox1.Text;
            command.Parameters.Add("@rP", SqlDbType.VarChar).Value = textBox2.Text;
            db.OpenSQL();
            if (command.ExecuteNonQuery() == 1)
            {
                MessageBox.Show("Аккаунт Создан");
            }else { MessageBox.Show("Аккаунт не Создан"); }
            db.ClodeSQL();
        }
    }
}

Сама ошибка