Problem with webservice consumption registered through Service reference

I have a problem with the consumption of WS registered by VS , the error that returns is related to the deserialization of the response.

Code:

using (ErpServiceSOAPPortClient service = new ErpServiceSOAPPortClient())
            {
                BoletoDTO _boleto = new BoletoDTO();
                _boleto.idNegociacao = 0;
                _boleto.pdf = "teste";

                ArrayOfBoletodto _arrBoletos = new ArrayOfBoletodto();
                _arrBoletos.item = new BoletoDTO[1];
                _arrBoletos.item[0] = _boleto;

                BoletosDTO _boletos = new BoletosDTO();
                _boletos.boletos = _arrBoletos;


               var _resp = service.enviarBoleto(1, _boletos);


            }

Exception:

System.ServiceModel.CommunicationException was unhandled by user code  HResult=-2146233087   Message=Error in deserializing body of reply message for operation 'enviarBoleto'.   Source=mscorlib   StackTrace:
    Server stack trace: 
       at System.ServiceModel.Dispatcher.XmlSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, XmlSerializer serializer, MessagePartDescription returnPart, MessagePartDescriptionCollection bodyParts, Object[] parameters, Boolean isRequest)
       at System.ServiceModel.Dispatcher.XmlSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest)
       at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)
       at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeReply(Message message, Object[] parameters)
       at System.ServiceModel.Dispatcher.ProxyOperationRuntime.AfterReply(ProxyRpc& rpc)
       at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
       at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
       at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
       at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
    Exception rethrown at [0]: 
       at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
       at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
       at WebApplication1.ServiceReference1.ErpServiceSOAPPort.enviarBoleto(Int32 numBoletos, BoletosDTO boletosDTO)
       at WebApplication1.ServiceReference1.ErpServiceSOAPPortClient.enviarBoleto(Int32 numBoletos, BoletosDTO boletosDTO) in C:\Users\marciel.torres\Documents\Visual Studio 2015\Projects\WebApplication1\WebApplication1\Service References\ServiceReference1\Reference.cs:line 835
       at WebApplication1._default.Page_Load(Object sender, EventArgs e) in C:\Users\marciel.torres\Documents\Visual Studio 2015\Projects\WebApplication1\WebApplication1\default.aspx.cs:line 29
       at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
       at System.Web.UI.Control.OnLoad(EventArgs e)
       at System.Web.UI.Control.LoadRecursive()
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)   InnerException: 
       HResult=-2146233079
       Message=There is an error in XML document (2, 738).
       Source=System.Xml
       StackTrace:
            at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events)
            at System.ServiceModel.Dispatcher.XmlSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, XmlSerializer serializer, MessagePartDescription returnPart, MessagePartDescriptionCollection bodyParts, Object[] parameters, Boolean isRequest)
       InnerException: 
            HResult=-2147467262
            Message=Cannot assign object of type WebApplication1.ServiceReference1.ResponseDTO to an object of type WebApplication1.ServiceReference1.ResponseDTO[].
            Source=1qxqreec
            StackTrace:
                 at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderErpServiceSOAPPort.Read7_ArrayOfResponsedto()
                 at System.Xml.Serialization.XmlSerializationReader.ReadReferencingElement(String name, String ns, Boolean elementCanBeType, String& fixupReference)
                 at System.Xml.Serialization.XmlSerializationReader.ReadReferencingElement(String name, String ns, String& fixupReference)
                 at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderErpServiceSOAPPort.Read6_ResponsesDTO()
                 at System.Xml.Serialization.XmlSerializationReader.ReadReferencingElement(String name, String ns, Boolean elementCanBeType, String& fixupReference)
                 at System.Xml.Serialization.XmlSerializationReader.ReadReferencingElement(String name, String ns, String& fixupReference)
                 at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderErpServiceSOAPPort.Read25_enviarBoletoResponse()
                 at Microsoft.Xml.Serialization.GeneratedAssembly.ArrayOfObjectSerializer5.Deserialize(XmlSerializationReader reader)
                 at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events)
            InnerException:

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