UIScrollView not scrolling in Swift

You need to set the frame of your UIScrollView so that it is less than the contentSize. Otherwise, it won't scroll.

Also, I would recommend that you add the following to your viewDidLoad method:

scroller.contentSize = CGSize(width: 400, height: 2300)

If you are using AutoLayout

Set content size in viewDidAppear which works for me.

override func viewDidAppear(_ animated: Bool) {
   scrollView.contentSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height+300)
}