System.Web.Services.Protocols.SoapHeaderException: Client not authenticated after processing available headers

I try to invoke method from my proxy class generated from a web reference added to the project , this is my code below 

public void call() { ystem.Net.ServicePointManager.ServerCertificateValidationCallback +=            (s, cert, chain, sslPolicyErrors) => true;            MonsterBusinessGatewayService gateway = new MonsterBusinessGatewayService();            RecruiterReferenceType rec = new RecruiterReferenceType();            CompanyAu ...