CXCallObserver not working in iPadOS 14

callObserver:callChanged:

Code Block 
import UIKit
import CallKit
class ViewController: UIViewController, CXCallObserverDelegate {    
    private lazy var callObserver = CXCallObserver()
    override func viewDidLoad() {
        super.viewDidLoad()
        configureCallButton()
        view.backgroundColor = .gray
        self.callObserver.setDelegate(self, queue: nil)
        // Do any additional setup after loading the view.
    }
    func configureCallButton() {
        let button = UIButton(type: .system)
        button.setTitle("Call", for: .normal)
        let attStr = NSMutableAttributedString(string: "Call", attributes: [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 25), NSAttributedString.Key.foregroundColor: UIColor.blue]);
        button.setAttributedTitle(attStr, for: .normal)
        button.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(button)
        button.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        button.addTarget(self, action: #selector(initiateCall), for: .touchUpInside)
    }
    @objc func initiateCall() {
        if let url = URL(string: "tel://*********") {
             UIApplication.shared.openURL(url)
         }
    }
    func callObserver(_ callObserver: CXCallObserver, callChanged call: CXCall) {
        if call.isOutgoing {
            print("Call outgoing")
        }
        else if call.hasConnected {
            print("Call has connected")
        }
        else if call.hasEnded {
            print("Call has ended")
        }
    }
}