navigation controller doesn't work - swift

Question

Signup UIViewController design that validates email, password and confirm password.
Signup is embedded in NavigationController
func showAlert(ttl:String,msg:String){
let alert = UIAlertController(title: "\(ttl)", message: "\(msg)", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
#IBAction func signUp(_ sender: UIButton) {
if (email.text != nil && password.text != nil && confrimPassword.text != nil){
if !(isValidEmail(testStr: email.text!)){
showAlert(ttl: "Invaild Email-ID", msg: "Please enter an valid Email-ID")
}
else if !(isValidPassword(testStr: password.text)){
showAlert(ttl: "Invalid Password", msg: "Password must have at least one uppercase,one digit,one lowercase and minimum 8 characters")
}
else if !(passwordMatch(password: password.text!, confirmPassword: confrimPassword.text!)){
showAlert(ttl: "Passwords doesn't Match", msg: "Please re-enter your password")
}
else{
if Connectivity.isConnectedToInternet {
Authentication.Signup(for: email.text!, password: password.text!,finished: { resdata in do{ let res = try JSONSerialization.jsonObject(with: resdata) as! Dictionary<String, AnyObject>
print(res)
DispatchQueue.main.async {
let view: Verification = self.storyboard?.instantiateViewController(withIdentifier: "Verify") as! Verification
view.email = self.email.text!
//doesnot work
self.navigationController?.pushViewController(view, animated: true)
}
}
catch{
print("Error")
}
})
}
else{
showAlert(ttl: "No Internet", msg: "Please check your internet connection")
}
}
}
else{
self.showAlert(ttl: "Enter all Credentials", msg: " ")
}
}
}
Tried using segue also that doesn't suit my requirements

Answer 1

#IBAction func signUp(_ sender: UIButton) {
Authentication.Signup(for: email.text!, password: password.text!,finished: { resdata in do{
let res = try JSONSerialization.jsonObject(with: resdata) as! Dictionary<String, AnyObject>
print(res)
DispatchQueue.main.async {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "Verify") as! Verification
controller.email = self.email.text!
self.present(controller, animated: true, completion: nil)
}
}