My CollectionViewController did not shows the DetailViewController. When Simultaneously clicking it shows the DetailViewController

Question

DetailViewController is not working and its my storyboard

CountryCollectionViewController

import Foundation
import UIKit

private let reuseIdentifier = "Cell"

class CountryCollectionViewController: UICollectionViewController {
    
    
    
    @IBAction func unwindToMain(segue: UIStoryboardSegue){
        
    }
    
    private var countries : [Country] = [ Country(image: "America", name: "America", text: "1. What is the Official Languages for America? \n Answer:- English.\n\n 2. What is the Capital city for United States of America? \n Answer:-  Washington, D.C.\n\n 3. What is the Currency for United States of America?? \n Answer:-  American Doller."),                     
        Country(image: "Vietnam", name: "Vietnam", text: "1. What is the Official Languages for Vietnam? \n Answer:-  Vietnamese.\n\n 2. What is the Capital city for Vietnam? \n Answer:-  Hanoi.\n\n 3. What is the Currency for Vietnam? \n Answer:-  Vietnamese dong.")]
    
    @IBOutlet var sideMenuBtn: UIBarButtonItem!


    override func viewDidLoad() {
        super.viewDidLoad()
        
        sideMenuBtn.target = self.revealViewController()
        sideMenuBtn.action = #selector(self.revealViewController()?.revealSideMenu)

    }

    // MARK: UICollectionViewDataSource

    override func numberOfSections(in collectionView: UICollectionView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }


    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of items
        return countries.count
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "dataCell", for: indexPath) as! CountryCollectionViewCell
    
        // Configure the cell
        
        let country = countries[indexPath.row]
        cell.countryImageView.image = UIImage(named: country.image)
        cell.countryNameLabel.text = country.name
    
        return cell
    }
    
    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        collectionView.deselectItem(at: indexPath, animated: false)
        performSegue(withIdentifier: "showDetail", sender: indexPath)
        
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        guard segue.identifier == "showDetail" else {
            return
        }
             let indexPath = sender as! IndexPath
                let destinationController = segue.destination as! CountryDetailViewController
                destinationController.country = countries[indexPath.row]
                //collectionView.deselectItem(at: indexPaths[0], animated: false)
            }
        }

CountryDetailViewController

import Foundation
import UIKit

class CountryDetailViewController: UIViewController {
    
    @IBOutlet var countryImageView:UIImageView!
    @IBOutlet weak var countryTextView: UITextView!
    @IBOutlet weak var countryLabel: UILabel!
    
    var country: Country!
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        countryLabel.text = country.name
        countryTextView.text = country.text
        countryImageView.image = UIImage(named: country.image)
    }
}

I'm new to xcode. My DetailViewController is not showing, IDK for why. If I try this example in separate project its works fine but, If I try this with my big project then it CountryCollectionViewController is loading but not DetailViewController. If I click simultaneously then only it displays. Can anyone Please help me from this issue. I attached my constraints errors also. Thanks in advance

2022-02-19 23:15:52.155204+0100 MultiTasker[20055:4485282] [LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each constraint and try to figure out which you don't expect; 
        (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x2804f83c0 UIImageView:0x141d63480.width == 100   (active)>",
    "<NSLayoutConstraint:0x2804fa530 H:|-(0)-[UIImageView:0x141d63480]   (active, names: '|':UIView:0x141d62f30 )>",
    "<NSLayoutConstraint:0x2804fa4e0 H:[UIImageView:0x141d63480]-(0)-|   (active, names: '|':UIView:0x141d62f30 )>",
    "<NSLayoutConstraint:0x2804f8b40 'UIIBSystemGenerated' MultiTasker.CountryCollectionViewCell:0x141d62ce0.leading == UIView:0x141d62f30.leading   (active)>",
    "<NSLayoutConstraint:0x2804fd0e0 'UIIBSystemGenerated' H:[UIView:0x141d62f30]-(0)-|   (active, names: '|':MultiTasker.CountryCollectionViewCell:0x141d62ce0 )>",
    "<NSLayoutConstraint:0x2804945a0 'UIView-Encapsulated-Layout-Width' MultiTasker.CountryCollectionViewCell:0x141d62ce0.width == 50   (active)>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x2804f83c0 UIImageView:0x141d63480.width == 100   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.
2022-02-19 23:15:52.156062+0100 MultiTasker[20055:4485282] [LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each constraint and try to figure out which you don't expect; 
        (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x2804fa620 UILabel:0x141d63650.width == 100   (active)>",
    "<NSLayoutConstraint:0x2804fa3f0 H:[UILabel:0x141d63650]-(0)-|   (active, names: '|':UIView:0x141d62f30 )>",
    "<NSLayoutConstraint:0x2804f9a40 H:|-(0)-[UILabel:0x141d63650]   (active, names: '|':UIView:0x141d62f30 )>",
    "<NSLayoutConstraint:0x2804f8b40 'UIIBSystemGenerated' MultiTasker.CountryCollectionViewCell:0x141d62ce0.leading == UIView:0x141d62f30.leading   (active)>",
    "<NSLayoutConstraint:0x2804fd0e0 'UIIBSystemGenerated' H:[UIView:0x141d62f30]-(0)-|   (active, names: '|':MultiTasker.CountryCollectionViewCell:0x141d62ce0 )>",
    "<NSLayoutConstraint:0x2804945a0 'UIView-Encapsulated-Layout-Width' MultiTasker.CountryCollectionViewCell:0x141d62ce0.width == 50   (active)>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x2804fa620 UILabel:0x141d63650.width == 100   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.
2022-02-19 23:15:52.156706+0100 MultiTasker[20055:4485282] [LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each constraint and try to figure out which you don't expect; 
        (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x2804f99f0 UIImageView:0x141d63480.height == 115   (active)>",
    "<NSLayoutConstraint:0x2804fa5d0 UILabel:0x141d63650.height == 35   (active)>",
    "<NSLayoutConstraint:0x2804fa490 V:|-(0)-[UIImageView:0x141d63480]   (active, names: '|':UIView:0x141d62f30 )>",
    "<NSLayoutConstraint:0x2804fa440 V:[UILabel:0x141d63650]-(0)-|   (active, names: '|':UIView:0x141d62f30 )>",
    "<NSLayoutConstraint:0x2804fa1c0 V:[UIImageView:0x141d63480]-(0)-[UILabel:0x141d63650]   (active)>",
    "<NSLayoutConstraint:0x2804fd090 'UIIBSystemGenerated' MultiTasker.CountryCollectionViewCell:0x141d62ce0.top == UIView:0x141d62f30.top   (active)>",
    "<NSLayoutConstraint:0x2804fd040 'UIIBSystemGenerated' V:[UIView:0x141d62f30]-(0)-|   (active, names: '|':MultiTasker.CountryCollectionViewCell:0x141d62ce0 )>",
    "<NSLayoutConstraint:0x2804945f0 'UIView-Encapsulated-Layout-Height' MultiTasker.CountryCollectionViewCell:0x141d62ce0.height == 50   (active)>"
)

Answer 1

I looked at your storyboard and I think the problem is in the second navigation controller. I tried to reproduce as much of your app as possible and the app crashes when I have the navigation controller between the CountryCollectionViewController and the CountryDetailViewController.

This navigation controller is not necessary anyway. Can you delete this navigation controller and see if your code works better?