System.Web.Services.Protocols.SoapException: Server was unable to process request - laravel

I want to send some parameter to an Asp web service. but I got this message error (I'm trying on my localhost):

  System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.NullReferenceException: Object reference not set to an instance of an object.
  at Service.SendSms(String cUserName, String cPassword, String cBody, String cSmsnumber, String cGetid, Int32 nCMessage, Int32 nTypeSent, String m_SchedulDate, String cDomainname, String cFromNumber, Int32 nSpeedsms, Int32 nPeriodmin, String cstarttime, String cEndTime)
  --- End of inner exception stack trace ---

my code :

  $parms['username'] = '***';
  $parms['password'] = '***';
  $parms['smsbody'] = 'test';
  $parms['smsNumber'] = '*****';
  $parms['Getid'] = '0';
  $parms['nCMessage'] = '1';
  $parms['cDomainName'] = '****';
  $parms['nTypeSent'] = '2';
  $parms['nSpeedsms'] = '';
  $parms['nPeriodmin'] = '';

  $client = new SoapClient("http://ift.tt/2kvqMmA");
  $status = $client->SendSms($parms); // error line

  dd($status);

via Chebli Mohamed