Custom buttons do not respond to touch - swift

Hi I have a ViewController that pops out when a cell in my collectionview is tapped. The issue I'm having is that the buttons at the top of my ViewController are not responding to being tapped.

Code for pop out view controller:

import UIKit

class PopUpCellViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

var expandedNoteTable: UITableView = UITableView()
let cellId = "cellId"
var picture: UIImage?
var comment: UILabel?

let addNBackgroundView: UIView = {
    let view = UIView()
    view.backgroundColor = UIColor(r: 244, g: 244, b: 255)
    view.translatesAutoresizingMaskIntoConstraints = false
    view.layer.cornerRadius = 8
    view.layer.masksToBounds = true
    return view
}()

lazy var addNButton: UIButton = {
    let button = UIButton(type: .system)
    button.setTitle("Add N", for: .normal)
    button.translatesAutoresizingMaskIntoConstraints = false
    button.isUserInteractionEnabled = true
    button.setTitleColor(UIColor(r: 88, g: 88, b: 88), for: .normal)
    button.titleLabel?.font = UIFont(name: "Nunito", size: 17)
    button.addTarget(self, action: #selector(handleTouch), for: .touchUpInside)
    return button
}()

let viewMBackgroundView: UIView = {
    let view = UIView()
    view.backgroundColor = UIColor(r: 244, g: 244, b: 255)
    view.translatesAutoresizingMaskIntoConstraints = false
    view.layer.cornerRadius = 8
    view.layer.masksToBounds = true
    return view
}()

lazy var viewMButton: UIButton = {
    let button = UIButton(type: .system)
    button.setTitle("M", for: .normal)
    button.translatesAutoresizingMaskIntoConstraints = false
    button.setTitleColor(UIColor(r: 88, g: 88, b: 88), for: .normal)
    button.titleLabel?.font = UIFont(name: "Nunito", size: 17)
    button.isUserInteractionEnabled = true
    button.addTarget(self, action: #selector(handleTouch), for: .touchUpInside)
    return button
}()

override func viewDidLoad() {
    super.viewDidLoad()

    view.addSubview(viewMBackgroundView)
    viewMBackgroundView.addSubview(viewMButton)
    view.addSubview(addNBackgroundView)
    addNBackgroundView.addSubview(addNButton)
    view.addSubview(expandedNoteTable)

    expandedNoteTable.frame = CGRect(x: 0, y: 67, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height - (67+49))
    expandedNoteTable.delegate = self
    expandedNoteTable.dataSource = self
    expandedNoteTable.separatorColor = UIColor.clear
    expandedNoteTable.register(ExpandedNoteTableViewCell.self, forCellReuseIdentifier: "cellId")

    self.view.backgroundColor = UIColor.white

    setConstraints()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func handleTouch() {

    print("button pressed")

}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 1
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: cellId) as! ExpandedNoteTableViewCell
    cell.imageView.image = picture
    cell.commentLabel.text = comment?.text
    return cell

}

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat{

    let pictureHeight = picture?.cgImage?.height

    return CGFloat(pictureHeight! + 1000)
}

func setConstraints() {

    viewMBackgroundView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -25).isActive = true
    viewMBackgroundView.topAnchor.constraint(equalTo: view.topAnchor, constant: ((self.navigationController?.navigationBar.frame.size.height)!/2)).isActive = true
    viewMBackgroundView.heightAnchor.constraint(equalToConstant: 35).isActive = true
    viewMBackgroundView.widthAnchor.constraint(equalToConstant: 90).isActive = true

    viewMButton.centerXAnchor.constraint(equalTo: viewMBackgroundView.centerXAnchor, constant: 10).isActive = true
    viewMButton.centerYAnchor.constraint(equalTo: viewMBackgroundView.centerYAnchor).isActive = true

    addNBackgroundView.rightAnchor.constraint(equalTo: viewMBackgroundView.leftAnchor, constant: -15).isActive = true
    addNBackgroundView.centerYAnchor.constraint(equalTo: viewMBackgroundView.centerYAnchor).isActive = true
    addNBackgroundView.heightAnchor.constraint(equalToConstant: 35).isActive = true
    addNBackgroundView.widthAnchor.constraint(equalToConstant: 95).isActive = true

    addNButton.centerXAnchor.constraint(equalTo: addNBackgroundView.centerXAnchor).isActive = true
    addNButton.centerYAnchor.constraint(equalTo: addNBackgroundView.centerYAnchor).isActive = true
}

}

try bellow code

let button:UIButton = UIButton(frame: CGRect(x: 100, y: 400, width: 100, height: 50))
    button.backgroundColor = .black
    button.setTitle("Button", for: .normal)
    button.addTarget(self, action:#selector(self.buttonClicked), for: .touchUpInside)
    self.view.addSubview(button)

    func buttonClicked() {
     print("Button Clicked")
    }