.NET 5 Return url not work

[sdktraceur]

This part of code in Login.razor dont work as expected in .NET 5

private async void HandleValidSubmit()
    {
        loading = true;
        try
        {
            await AuthenticationService.Login(model.Username, model.Password);
            var returnUrl = NavigationManager.QueryString("returnUrl") ?? "/";
            NavigationManager.NavigateTo(returnUrl);
        }
        catch (Exception ex)
        {
            error = ex.Message;
            loading = false;
            StateHasChanged();
        }
    }