whose view is not in the window hierarchy

I am developing a game and I am trying to move from my game scene to my view controller but it gives me the error:

Error: Warning: Attempt to present <Breakout.GameViewController: 0x7f8874d19ed0> on whose view is not in the window hierarchy!.

My game is set up so I do level 1 and finish it then it takes me to the vc where I can do level 1. That works, but then when I finish level 2 and try to go back to the vc, it does not work and gives me the error.

I have looked at other posts but nothing has directly linked to this.

My Game Scene Controller:

    class Level1: SKScene,SKPhysicsContactDelegate {
        var ball:SKSpriteNode!
        var paddle:SKSpriteNode!
        var scoreLabel:SKLabelNode!
        var score:Int = 0 {
            didSet{
                scoreLabel.text = "Score:\(score)"
            }
        }
       
        override func didMove(to view: SKView) {
            ball = self.childNode(withName: "Ball") as! SKSpriteNode
            paddle = self.childNode(withName: "Paddle") as! SKSpriteNode
            scoreLabel = self.childNode(withName: "Score") as! SKLabelNode
           
            ball.physicsBody?.applyImpulse(CGVector(dx: 50, dy: 50))
            ball.physicsBody?.mass=0.1
            let border = SKPhysicsBody(edgeLoopFrom: (view.scene?.frame)!)
            border.friction = 0
           
            self.physicsBody = border
            ball.physicsBody?.mass = 0.09
            self.physicsWorld.contactDelegate = self
        }
       
        override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
            for touch in touches {
                let touchLocation = touch.location(in: self)
                paddle.position.x = touchLocation.x
            }
        }
       
        override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
            for touch in touches {
                let touchLocation = touch.location(in: self)
                paddle.position.x = touchLocation.x
            }
        }
       
       
        func didBegin(_ contact: SKPhysicsContact) {
            let bodyAName = contact.bodyA.node?.name
            let bodyBName = contact.bodyB.node?.name
           
            if bodyAName == "Ball" && bodyBName == "Brick" || bodyAName == "Brick" && bodyBName == "Ball"{
                if bodyAName == "Brick" {
                    contact.bodyA.node?.removeFromParent()
                    score += 1
                } else if bodyBName == "Brick" {
                    contact.bodyB.node?.removeFromParent()
                    score += 1
                }
            }
        }
       
        override func update(_ currentTime: TimeInterval) {
            if (score == 9) {
                scoreLabel.text = "You Won!"
                self.view?.isPaused = true
                sleep(2)
                let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
                let vc = mainStoryboard.instantiateViewController(withIdentifier: "GameViewController")
                self.view?.window?.rootViewController?.present(vc, animated: true, completion: nil)
                level1done = true
            }
            if (ball.position.y < paddle.position.y) {
                scoreLabel.text = "You Lost!"
                self.view?.isPaused = true
                sleep(2)
                let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
                let vc = mainStoryboard.instantiateViewController(withIdentifier: "GameViewController")
                self.view?.window?.rootViewController?.present(vc, animated: true, completion: nil)
            }
        }
    }