using System;
using System.Runtime.Serialization;
using System.ServiceModel;

namespace EmailService
{
    [ServiceContract]
    public class EmailValidator
    {
        [DataContract]
        public class EmailValidatorFault
        {
            private string CustomError;
            public EmailValidatorFault(string error)
            {
                CustomError = error;
            }

            [DataMemberAttribute]
            public string Message
            {
                get { return this.CustomError; }
                set { this.CustomError = value; }
            }

            [DataMemberAttribute]
            public string Reason
            {
                get { return this.CustomError; }
                set { this.CustomError = value; }
            }

        }

        [OperationContract]
        [FaultContract(typeof(EmailValidatorFault))]
        public string Test()
        {
            try
            {
                int a = 0;
                int b = 1 / a; //Преднамеренное исключение
                return "Hello, World!";
            }
            catch (Exception e)
            {
                FaultException fe = new FaultException<EmailValidatorFault>(new EmailValidatorFault(e.Message));
                throw fe;
            }
        }
    }
}

using System;
using System.ServiceModel;

namespace ConsoleClient
{
    class Program
    {
        static void Main(string[] args)
        {
            EmailValidatorClient svc = new EmailValidatorClient();
            try
            {
                string Result = svc.Test();
                Console.WriteLine("Result = {0}", Result);
            }
            catch (FaultException<EmailValidatorClient> e)
            {
                Console.WriteLine(e.Message);
            }
            Console.Write("Input Enter to Exit ");
            Console.Read();
        }
    }
}

catch (FaultException<EmailValidatorEmailValidatorFault> e)
   {
   Console.WriteLine(e.Detail.Message);
   }

catch (FaultException<EmailValidatorClient> e)
   {
    Console.WriteLine(e.Message);
   }