Navigation coming back to the previous view controller

Question

I am trying to navigate to a ViewController but after a second the ViewController just disappears and the old one shows.

Here is the function for the navigation:

private func NavigateToManagerMenu() {
    let MainStoryboard = UIStoryboard(name: "Main", bundle: Bundle.main)
    guard let MainNavigationVC = MainStoryboard.instantiateViewController(withIdentifier: "MianNavigationController") as? MainNavigationController else{return}
    present(MainNavigationVC, animated: true, completion: nil)
}

it called from the button Action:

@IBAction func ArrowAction(_ sender: Any) {
    if mode == "signup"{
        if CheckSignUp(){
            SignUp()
            NavigateToManagerMenu()
        }
    }
    if mode == "login"{
        if CheckLogin(){
            LogIn()
            NavigateToManagerMenu()
        }
    }
}