В чем ошибка при использовании класса обертки для WCF?

public class ClassResultInfo
    {
        [DataMember(Name = "Статус")]
        public bool Status { get; set; }
        [DataMember(Name = "Тип_Результата")]
        public Type TypeResult{ get; set; }
        [DataMember(Name = "Результат")]
        public object Result { get; set; }
        [DataMember(Name = "Ошибка")]
        public string Error { get; set; }

        public ClassResultInfo()
        {
        }

        public ClassResultInfo(bool status, string error)
        {
            Status = status;
            TypeResult = null;
            Result = null;
            Error = error;
        }

        public ClassResultInfo(bool status, Type typeResult, object result)
        {
            Status = status;
            TypeResult = typeResult;
            Result = result;
            Error = string.Empty;
        }

        public ClassResultInfo(bool status, string error, Type typeResult, object result )
        {
            Status = status;
            TypeResult = typeResult;
            Result = result;
            Error = error;
        }
    }

public interface IAisaServer
    {
        [OperationContract(Name = "Мониторинг")]
        ClassResultInfo MonitoringServiceList(User user, bool isActive);
    }