Начал изучать SQL,и столкнулся с проблемой "Система конфигурации не прошла инициализацию"(Использую VS)

Форма:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Configuration;
using System.Data.SqlClient;


namespace WindowsFormsApp4
{
    public partial class Form1 : Form
    {
        private SqlConnection sqlconn = null;
        public Form1()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, MouseEventArgs e)
        {
            sqlconn = new SqlConnection(ConfigurationManager.ConnectionStrings["test"].ConnectionString);

            sqlconn.Open();
            
            if(sqlconn.State == ConnectionState.Open)
            {
                MessageBox.Show("Подключено");
            }
        }
    }
}

AppConfig:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
    </startup>
    <ConnectionStrings>
    <add name = "test" connectionStrings = "Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\Darknest Void\source\repos\WindowsFormsApp4\Database1.mdf;Integrated Security=True"/>
    </ConnectionStrings>
</configuration>`