Squareup付款网关Api错误请求400

Question

1. 这是我收到错误请求的地方

   <script type="text/javascript">
       $(function () {
           var model = @(Html.Raw(JsonConvert.SerializeObject(Model, new JsonSerializerSettings {ContractResolver = new ExcludePropertiesContractResolver()})));
           model["A1"] = '@ViewData["A1"]';
           model["A2"] = '@ViewData["A2"]';
           model["A3"] = '@ViewData["A3"]';
           var viewModel = new ABC.SelectABC(model);
           ko.applyBindings(viewModel);
       });
   </script>
   

2. 在这行代码中我收到了错误的请求。

   public void OnPost(string nonce)
   {
       TransactionsApi transactionsApi = new TransactionsApi();
       string uuid = NewIdempotencyKey();
       Money amount = new Money(1, Money.CurrencyEnum.USD);
       ChargeRequest body = new ChargeRequest(AmountMoney: amount, IdempotencyKey: uuid, CardNonce: nonce);
   
       try
       {