ASP.NET C# Object reference not set to an instance of an object. at System.Web.Services.Protocols.SoapClientType..ctor

Question

UPDATE SEND TO VDWWD who close my question.Please pay attention and read my question completly before making your decision. My code exception in 'new x();' initialize constructor? and it not jump inside initialize constructor function. I tried every thing i can, and I'm sure that my problem is not resolved in https://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it

I got a big problem with my project. I used SOAP to call SMSBRANDNAME API:

Controller:

try
{
  string phone = sender.phone;
  string smsContent = sender.smsContent;
  string username = sender.username;
  string password = sender.password;
  string cpCode = sender.cpCode;
  string serviceID = sender.serviceID;
  string commandCode = sender.commandCode;
  BulkApi api = new BulkApi();<<<== **CODE THROW EXCEPTION HERE**
  api.Timeout = 6000;
  result r = api.wsCpMt(username, password, cpCode, "1", phone, phone, serviceID, commandCode, smsContent, "F");

  if (r.result1 == 1)
  {
      return new SMSResult()
      {
          status = "success",
          message = "Gửi tin thành công!",
          errorCode = r.message
      };
  }
  else
  {
      return new SMSResult()
      {
          status = "fail",
          message = "Gửi tin thất bại!",
          errorCode = r.message
      };
  }
}
catch (Exception ex)<<<== **I GOT EXCEPTION HERE**
{
  return new SMSResult()
  {
      status = "error",
      message = "Đã có lỗi xảy ra!",
      errorCode = ex.ToString()
  }; 
}   

Function in BulkAPI.cs:

[System.CodeDom.Compiler.GeneratedCodeAttribute("wsdl", "2.0.50727.3038")]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Web.Services.WebServiceBindingAttribute(Name="CcApiPortBinding", Namespace="http://impl.bulkSms.ws/")]
public class BulkApi : System.Web.Services.Protocols.SoapHttpClientProtocol
{

  private System.Threading.SendOrPostCallback getIpOperationCompleted;

  private System.Threading.SendOrPostCallback checkBalanceOperationCompleted;

  private System.Threading.SendOrPostCallback wsCpMtOperationCompleted;

  private System.Threading.SendOrPostCallback wsReportHourOperationCompleted;

  private System.Threading.SendOrPostCallback wsReportDailyOperationCompleted;

  private System.Threading.SendOrPostCallback wsReportMonthOperationCompleted;

  private System.Threading.SendOrPostCallback getFailSubOperationCompleted;


  public BulkApi()
  {               <<<<= **I PUT BREAK POINT HERE BUT CODE NO JUMP IN**
      this.Url = "https://ams.tinnhanthuonghieu.vn:8998/bulkapi?wsdl";
  }

  public event getIpCompletedEventHandler getIpCompleted;


  public event checkBalanceCompletedEventHandler checkBalanceCompleted;


  public event wsCpMtCompletedEventHandler wsCpMtCompleted;

  ............

I got this exception:

{System.NullReferenceException: Object reference not set to an instance of an object. at System.Web.Services.Protocols.SoapClientType..ctor(Type type) at System.Web.Services.Protocols.SoapHttpClientProtocol..ctor() at BulkApi..ctor() in E:\Project\HtxThienHuong\HTXThienHuong\Services\BulkAPI\BulkApi.cs:line 25 at BulkApp.BulkSMS.SendSMS(BulkDto sender) in E:\Project\HtxThienHuong\HTXThienHuong\Services\BulkAPI\BulkSMS.cs:line 47}

I don't know how to fix it and why it wrong, please save me. Thank you all!