UITableView not appearing properly using constraints - ios

Question

I'm having problems displaying this UITableView under the UIImageView. It does this weird thing, where you can't see the table or anything at all, however when you scroll up or down, you can see the blue cell appear in the 40px high UITableView.
class TvDetailHeader: UICollectionViewCell, UITableViewDelegate, UITableViewDataSource {
private let contributorCellId = "contributorCellId"
let thumbnailImageView: UIImageView = {
let imageView = UIImageView(image: #imageLiteral(resourceName: "stranger things poster"))
imageView.translatesAutoresizingMaskIntoConstraints = false
imageView.layer.cornerRadius = 6
imageView.contentMode = .scaleAspectFill
imageView.layer.masksToBounds = true
return imageView
}()
let contributorTableView: UITableView = {
let tableView = UITableView()
tableView.separatorStyle = .none
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.backgroundColor = .blue
return tableView
}()
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: contributorCellId, for: indexPath) as! ContributorCell
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 40
}
override func setupViews() {
super.setupViews()
contributorTableView.delegate = self
contributorTableView.dataSource = self
contributorTableView.register(ContributorCell.self, forCellReuseIdentifier: contributorCellId)
backgroundColor = .white
addSubview(thumbnailImageView)
addSubview(contributorTableView)
thumbnailImageView.topAnchor.constraint(equalTo: topAnchor, constant: 25).isActive = true
thumbnailImageView.leftAnchor.constraint(equalTo: leftAnchor, constant: 20).isActive = true
thumbnailImageView.widthAnchor.constraint(equalToConstant: 60).isActive = true
thumbnailImageView.heightAnchor.constraint(equalToConstant: 90).isActive = true
contributorTableView.topAnchor.constraint(equalTo: thumbnailImageView.bottomAnchor, constant: 10).isActive = true
contributorTableView.leftAnchor.constraint(equalTo: leftAnchor, constant: 20).isActive = true
contributorTableView.widthAnchor.constraint(equalToConstant: frame.width).isActive = true
contributorTableView.heightAnchor.constraint(equalToConstant: 40).isActive = true
}
}
class ContributorCell: UITableViewCell {
let cellView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setupViews() {
addSubview(cellView)
backgroundColor = .blue
cellView.topAnchor.constraint(equalTo: topAnchor, constant: 0).isActive = true
cellView.leftAnchor.constraint(equalTo: leftAnchor, constant: 0).isActive = true
cellView.widthAnchor.constraint(equalToConstant: 30).isActive = true
cellView.heightAnchor.constraint(equalToConstant: frame.height).isActive = true
}
}