Login OK mais erreur js interop ensuite

BlazorPolicyAuth/Components/Pages/Account/Login.razor

@@ -49,13 +49,14 @@
 </div>
 
 @code {
-    private UserLogin user = new();
+    [SupplyParameterFromForm] private UserLogin user { get; set; }
     private string errorMessage = string.Empty;
     private string returnUrl = string.Empty;
     private bool rememberMe;
     
     protected override void OnInitialized()
     {
+        user ??= new();
         var uri = NavigationManager.ToAbsoluteUri(NavigationManager.Uri);
         NameValueCollection queryStringCall = HttpUtility.ParseQueryString(uri.Query);