我正在开发一个ios应用程序（Swift 5），我试图在应用程序离线时显示一个屏幕，然后在用户重新连接时关闭。
我希望OfflineViewController在用户离线时出现，如果用户已连接，则会出现用户最后一个屏幕。
当我断开网络连接时，OfflineViewController会出现，但当我重新连接到网络时，OfflineViewController不会消失。我尝试添加一个按钮来关闭，但也不起作用。
我在下面附上了我的代码，你知道我做错了什么吗？

场景代理

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    let reachability = try! Reachability()

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        
        guard let _ = (scene as? UIWindowScene) else { return }

        // Send to homepage if logged in, otherwise login screen.
        let accessToken: String? = KeychainWrapper.standard.string(forKey: "accessToken")
        
        // If access token exists, skip login page
        if accessToken != nil {            
            if let windowScene = scene as? UIWindowScene {
                self.window = UIWindow(windowScene: windowScene)
                let mainStoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
                let vc = mainStoryboard.instantiateViewController(withIdentifier: "homeTabController") as! TabBarController
                self.window!.rootViewController = vc
            }
        }

        reachability.whenUnreachable = { [self] _ in
            print("Not reachable (Scene delegate)")

            let storyboard = UIStoryboard(name: "Main", bundle: nil)
            
            let vc = storyboard.instantiateViewController(withIdentifier: "OfflineViewController") as! OfflineViewController
            vc.modalPresentationStyle = .fullScreen

            guard let firstScene = UIApplication.shared.connectedScenes.first as? UIWindowScene else {
                return
            }

            guard let firstWindow = firstScene.windows.first else {
                return
            }
            
            let rootVC = firstWindow.rootViewController
            rootVC?.dismiss(animated: true, completion: nil)
            rootVC!.present(vc, animated: true, completion: nil)

        }

        do {
            try reachability.startNotifier()
        } catch {
            print("Unable to start notifier")
        }
    }
}

脱机视图控制器

import UIKit

class OfflineViewController: UIViewController {
    
    let reachability = try! Reachability()

    override func viewDidLoad() {
        super.viewDidLoad()

        do {
            try reachability.startNotifier()
        } catch {
            print("Unable to start notifier")
        }
    }
    
    @IBAction func hitRefresh(_ sender: Any) {
        reachability.whenReachable = { reachability in
                self.dismiss(animated: true, completion: nil)
        }
    }
}