Image passed from an API not displaying in a pageview container swift

I am working on an iOS application which interacts with an API using alamofire and swiftyJSON. In this api I get a bunch of values returned and one of them is images. the Images returned comes in form of an array but i am able to iterate through the array and display a single image. To make the application more advanced, I decided to implement UIPageViewController class in my application. I called the API function and tried to pass my images into view controllers.
List of things in my storyboard

1. A UIPageView
2. A UiViewController with a UIImage embeded into it.

I have my codes fine to the best of my knowledge but when I run the application nothing happens on in the console. Below is my codes.

protocol ProductImagesPageViewControllerDelegate: class {
    func setupPageController(numberOfPages: Int)
    func turnPageController(to index: Int)
}

class ProductPageVC: UIPageViewController {

    weak var  pageViewControllerDelegate: ProductImagesPageViewControllerDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        automaticallyAdjustsScrollViewInsets = false
        dataSource = self
        delegate = self

    }


    func configureImg() {
        let productId = ProductServices.instance.selectedProduct?.id
        ProductServices.instance.findIndividualProducts(id: productId!, completion: { (success) in

            if success {
                ProductServices.instance.productDetails.forEach({ (productDetail) in

                    let images = productDetail.productImg.count

                    if images > 0 {

                        for image in 0..<(images) {

                            let imageVC = self.storyboard?.instantiateViewController(withIdentifier: PRODUCT_IMAGE_VC)
                            self.controllers.append(imageVC!)

                        }
                    }

                })
            }
        })
    }

    lazy var controllers: [UIViewController] = {

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        var controllers = [UIViewController]()


        let productId = ProductServices.instance.selectedProduct?.id
        ProductServices.instance.findIndividualProducts(id: productId!, completion: { (success) in

            if success {
                ProductServices.instance.productDetails.forEach({ (productDetail) in

                    let images = productDetail.productImg.count

                    if images > 0 {

                        for image in 0..<(images) {

                            let imageVC = storyboard.instantiateViewController(withIdentifier: PRODUCT_IMAGE_VC)
                            controllers.append(imageVC)

                        }
                    }

                })
            }
        })



        self.pageViewControllerDelegate?.setupPageController(numberOfPages: controllers.count)

        return controllers
    }()



    func turnToPage(index: Int)
    {
        let controller = controllers[index]
        var direction = UIPageViewControllerNavigationDirection.forward

        if let currentVC = viewControllers?.first {
            let currentIndex = controllers.index(of: currentVC)!
            if currentIndex > index {
                direction = .reverse
            }
        }

        self.configureDisplaying(viewController: controller)

        setViewControllers([controller], direction: direction, animated: true, completion: nil)
    }

    func configureDisplaying(viewController: UIViewController)
    {
        for (index, vc) in controllers.enumerated() {
            if viewController === vc {
                if let imageVC = viewController as? ImagesVC {

                    imageVC.configureImage(productIndex: index)

                    self.pageViewControllerDelegate?.turnPageController(to: index)
                }
            }
        }
    }
}
// MARK: - UIPageViewControllerDataSource

extension ProductPageVC : UIPageViewControllerDataSource
{
    func pageViewController(_ pageViewController: UIPageViewController, 
viewControllerBefore viewController: UIViewController) -> UIViewController?
    {
        if let index = controllers.index(of: viewController) {
            if index > 0 {
                return controllers[index-1]
            }
        }

        return controllers.last
    }

    func pageViewController(_ pageViewController: UIPageViewController, 
viewControllerAfter viewController: UIViewController) -> UIViewController? {

        if let index = controllers.index(of: viewController) {
            if index < controllers.count - 1 {
                return controllers[index + 1]
            }
        }

        return controllers.first
    }
}

extension ProductPageVC : UIPageViewControllerDelegate {

    func pageViewController(_ pageViewController: UIPageViewController, 
willTransitionTo pendingViewControllers: [UIViewController])
    {
        self.configureDisplaying(viewController: pendingViewControllers.first as! ImagesVC)
    }

    func pageViewController(_ pageViewController: UIPageViewController, 
didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], 
transitionCompleted completed: Bool)
    {
        if !completed {
            self.configureDisplaying(viewController: previousViewControllers.first as! 
ImagesVC)
        }
    }
}

This is my ImageVC code

class ImagesVC: UIViewController {

    @IBOutlet weak var imageView: UIImageView!


    func configureImage(productIndex : Int) -> Void {

        ProductServices.instance.productDetails.forEach { (productImg) in

            if productImg.productImg.count > 0 {
                imageView.sd_setImage(with: URL(string: productImg.productImg[productIndex]!) )
            } else {
                imageView.image = UIImage(named: "image_not_found")
            }
        }

    }}

This is my HeaderImageView code

class HeaderImageVC: UIView {

    @IBOutlet weak var pageControl: UIPageControl!
}

extension HeaderImageVC : ProductImagesPageViewControllerDelegate {
    func setupPageController(numberOfPages: Int)
    {
        pageControl.numberOfPages = numberOfPages
    }

    func turnPageController(to index: Int)
    {
        pageControl.currentPage = index
    }
}

I have no idea why the code is not working buth further codes would be supplied on request. Thanks.


from Image passed from an API not displaying in a pageview container swift