Why does ap.Connect(authrequest) return a null value?

Question

I am having a problem with my code where i run into an error when i try to click the join button. It says the ap.Connect(authrequest) is returning a null value so it cannot return a bool value. I am doing this in visual studio in a .net forms i think. Thanks for you help.

Ps i am a student

 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 SimpleWifi;
    
    namespace desk_flat
    {
        public partial class formConnect : Form
        {
            private static Wifi wifi;
    
            public formConnect()
            {
                InitializeComponent();
               
            }
    
            private void Form1_Load(object sender, EventArgs e)
            {
                wifi = new Wifi();
                List<AccessPoint> aps = wifi.GetAccessPoints();
                foreach (AccessPoint ap in aps)
                {
                    ListViewItem listobj = new ListViewItem(ap.Name);
                    listobj.SubItems.Add(ap.SignalStrength + "'''");
                    listobj.Tag = ap;
    
                    lstWifi.Items.Add(listobj);
    
                }
            }
    
            private bool ConnectWifi(AccessPoint ap, string password)
            {
                AuthRequest authrequest = new AuthRequest(ap);
                authrequest.Password = password;
                return ap.Connect(authrequest);
            }
    
            private void btnJoin_Click(object sender, EventArgs e)
            {
                if (lstWifi.Items.Count > 0 && txtbPassword.Text.Length > 0)
                {
                    ListViewItem selectedItem = lstWifi.SelectedItems[0];
                    AccessPoint ap = (AccessPoint)selectedItem.Tag;
                    if (ConnectWifi(ap, txtbPassword.Text))
                    {
                        lblStatus.Text = "You have connected to " + ap.Name;
                    }
                    else
                    {
                        lblStatus.Text = "Connection has failed";
                    }
                }
                else
                {
                    lblStatus.Text = "Enter a password or select a network";
                }
            
            }
        }
    }