WKWebView requires new login

Question

Code below is very simple. I use WKWebView to login to my Microsoft account.

class MSAuthenticationViewController: UIViewController, WKUIDelegate, WKNavigationDelegate {
    
    @IBOutlet var webView: WKWebView!
    @IBOutlet var DoneBonnon: UIBarButtonItem!
    @IBOutlet var RefreshButton: UIBarButtonItem!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        self.webView.getCookies() { cookies in // for debug
            print("# of cookies", cookies.count)
        }
        
        let websiteDataStore = WKWebsiteDataStore.default()
        let configuration = WKWebViewConfiguration()
        configuration.websiteDataStore = websiteDataStore
        webView = WKWebView(frame: view.frame, configuration: configuration)
        webView.uiDelegate = self
        webView.navigationDelegate = self
        let url = URL(string: "https://login.microsoftonline.com")!
        let request = URLRequest(url: url)
        webView.load(request)
        view = webView
    }
}

I close the controller by swiping it down. When I open it again, I have to re-login despite the number of cookies didn't change. Basically this means, that closing the controller logs me out.

My aim is to stay logged in, meaning when I open the controller again, that I'm still logged in.

What do I miss?