push view controller doesn't work from collection view cell

Question

when I try to navigate new view controller the code run but don't do the job

the code for cell :

protocol NavigateViewControllerDelegate {
    func navigate(destination : String)
}

class LoginCell : UICollectionViewCell {
    var delegate : NavigateViewControllerDelegate?

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }

    func setupViews () {
        ...
        loginButton.addTarget(self, action: #selector(login), for: .touchUpInside)
        ...
    }

    @objc func login(){
        ...
        self.delegate = ViewController() as NavigateViewControllerDelegate
        self.delegate.navigate(destination: "MainMenu")
        ...
    }
}

and in the view controller :

class ViewController : UICollectionViewController,NavigateViewControllerDelegate {
    ...
    func navigate(destination: String){
        print("navigate to main menu")
        self.navigationController?.pushViewController(MainMenuVC(), animated: true)
    }
}

the code run and the print instruction done and print "navigate to main menu" in consul but the app didn't navigate Main menu view controller