UIImpactFeedbackGenerator is Not Working? UIKit - Xcode 13.4.1 - Swift 5

I want to generate vibration when I press the button but I get no results.

Helper class I created to manage vibrations:

import Foundation
import UIKit

final class HapticsManager{
    static let shared = HapticsManager()
    
    private init(){}
    
    public func selectionVibrate(){
        DispatchQueue.main.async {
            let selectionImpactGenerator = UIImpactFeedbackGenerator()
            selectionImpactGenerator.prepare()
            selectionImpactGenerator.impactOccurred()
        }
    }
    
    public func haptic(for type: UIImpactFeedbackGenerator.FeedbackStyle){
        DispatchQueue.main.async {
            let notificationGenerator = UIImpactFeedbackGenerator()
            notificationGenerator.prepare()
            notificationGenerator.impactOccurred()
        }
    }
}

in ViewDidLoad()

  override func viewDidLoad() {
        super.viewDidLoad()
        HapticsManager.shared.selectionVibrate()
        addTargets()
        setStartGradientView()
        showLayout()
    }

Function of button with click target added:

    @objc fileprivate func setButtonClicked(){
        HapticsManager.shared.haptic(for: .heavy)
    }

I tried many methods but no result.

Thanks...

There is no problem about your code but needs some additional information. You need to check if device hardware is support for CHHapticEngine like that;

public func haptic(for type: UIImpactFeedbackGenerator.FeedbackStyle) {
    if CHHapticEngine.capabilitiesForHardware().supportsHaptics {
        let notificationGenerator = UIImpactFeedbackGenerator()
        notificationGenerator.prepare()
        notificationGenerator.impactOccurred()
    } else {
        AudioServicesPlaySystemSound(1520)
    }
}