my leet code

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 MySql.Data.MySqlClient;
using System.Windows.Forms;

namespace volgerschool
{
    public partial class Formregister : Form
    {
        private MySqlConnection conn;
        private string server;
        private string database;
        private string uid;
        private string password;

        public Formregister()
        {
            server = "127.0.0.1";
            database = "svs";
            uid = "svs";
            password = "kaas123";

            string connString;
            connString = $"SERVER={server};DATABASE={database};UID={uid};PASSWORD={password};";

            conn = new MySqlConnection(connString);
            InitializeComponent();
        }
        //login
        private void button1_Click(object sender, EventArgs e)
        {
            string user = textBox1.Text;
            string pass = textBox2.Text;
            if (IsLogin(user, pass))
            {
                MessageBox.Show($"Welkom {user}");
            }
            else
            {
                MessageBox.Show($"Sorry {user}, de login is niet gelukt");
            }
        }
        //register
        private void button2_Click(object sender, EventArgs e)
        {
            string user = textBox1.Text;
            string pass = textBox2.Text;
            if (Register(user, pass))
            {
                MessageBox.Show($"Welkom {user}");
            }
            else
            {
                MessageBox.Show($"Sorry {user}, Het is niet gelukt");    ///THIS IS WHERE IT BREAKS///
            }

        }

        public bool Register(string user, string pass)
        {
            string query = $"INSTERT INTO users (id, naam, password) VALUES ('', '{user}', '{pass}');";

            try
            {
                if (OpenConnection())
                {
                    MySqlCommand cmd = new MySqlCommand(query, conn);

                    try
                    {
                        cmd.ExecuteNonQuery();
                        return true;
                    }
                    catch (Exception ex)
                    {
                        return false;
                    }
                }
                else
                {
                    conn.Close();
                    return false;
                }
            }
            catch (Exception ex)
            {
                conn.Close();
                return true;
            }
        }
        public bool IsLogin(string user, string pass)
        {
            string query = $"SELECT FROM users WHERE naam ='{user}' AND password ='{pass}';";

            try
            {
                if (OpenConnection())
                {
                    MySqlCommand cmd = new MySqlCommand(query, conn);
                    MySqlDataReader reader = cmd.ExecuteReader();

                    if (reader.Read())
                    {
                        reader.Close();
                        conn.Close();
                        return true;
                    }
                    else
                    {
                        reader.Close();
                        conn.Close();
                        return false;
                    }
                }
                else
                {
                    conn.Close();
                    return false;
                }

            }
            catch(Exception ex)
            {
                conn.Close();
                return false;
            }

        }
        private bool OpenConnection()
        {
            try
            {
                conn.Open();
                return true;
            }
            catch (MySqlException ex)
            {
                switch (ex.Number)
                {
                    case 0:
                        MessageBox.Show("Connectie met server gefaalt");
                        break;
                    case 1045:
                        MessageBox.Show("Server credentials incorrect");
                        break;

                }
                return false;
            }
        }

    }
}