public async Task <IActionResult> OnGetAsync(bool rememberMe, string email, string returnUrl = null)
        {
            // Ensure the user has gone through the username & password screen first
            var userId = await _authenticatorService.GetAuthenticationUserId();

            if (String.IsNullOrEmpty(userId))
            {
                throw new InvalidOperationException($"Unable to load two-factor authentication user.");
            }

            ReturnUrl  = returnUrl;
            RememberMe = rememberMe;
            Email      = email;

            return(Page());
        }