Service does not execute controller method

This message I get in the browser or postman

  

"Message": "No HTTP resources were found matching the   Request URI ' link '. ",       "MessageDetail": "No action was found in the Items Controller that matches the request."

The problem is that I'm building a service where I pass an ID in the url so that only the items in that budget come in. In the controller it looks like this:

public class ItensController : ApiController
    {
        AutorizadorContext contexto = new AutorizadorContext();
        ItensLiberacao itens = new ItensLiberacao();

        [AcceptVerbs("Get")]
        public IEnumerable<ItensLibDTO> getItensLiberacao(int idorcamento)
        {
            return itens.getItensLib(idorcamento).AsEnumerable().ToList();
        }
    }

And here the class ItemsLiberation:

public class ItensLiberacao
    {
        AutorizadorContext contexto = new AutorizadorContext();
        ItensLibDTO libDTO = new ItensLibDTO();

        public List<ItensLibDTO> getItensLib(int idorcamento)
        {
            var lista = contexto.ItensLibs
                .Where(itens => itens.IdOrcamento == idorcamento)
                .Select(item => new ItensLibDTO
                {
                    Produto = item.Produto,
                    Qtde = item.Qtde.ToString(),
                    Unitario = item.Unitario.ToString(),
                    Custo = item.Custo.ToString(),
                    CustoDiario = item.CustoDiario.ToString(),
                    UltCondicao = item.UltCondicao.ToString(),
                    Total = item.Total.ToString()
                }).ToList();

            return lista;
        }
    }

How do I resolve this? What is missing most for the service to work? The number: 1000012105 is the ID of an existing budget in the database.

EDIT1

I changed my service to this and the same error continues:

[AcceptVerbs("Get")]
        public HttpResponseMessage getItensLiberacao(int idorcamento)
        {
            var _itens = contexto.ItensLibs.Where(it => it.IdOrcamento == idorcamento).FirstOrDefault();
            return Request.CreateResponse(HttpStatusCode.OK, _itens);

        }

EDIT2

If I change the method and the service works, like this:

public class ItensLiberacao
    {
        AutorizadorContext contexto = new AutorizadorContext();
        ItensLibDTO libDTO = new ItensLibDTO();

        public List<ItensLibDTO> getItensLib()
        {
            var lista = contexto.ItensLibs
                //.Where(itens => itens.IdOrcamento == idorcamento)
                .Select(item => new ItensLibDTO
                {
                    Produto = item.Produto,
                    Qtde = item.Qtde.ToString(),
                    Unitario = item.Unitario.ToString(),
                    Custo = item.Custo.ToString(),
                    CustoDiario = item.CustoDiario.ToString(),
                    UltCondicao = item.UltCondicao.ToString(),
                    Total = item.Total.ToString()
                }).ToList();

            return lista;
        }
    }

And the service:

public class ItensController : ApiController
    {
        AutorizadorContext contexto = new AutorizadorContext();
        ItensLiberacao itens = new ItensLiberacao();

        [AcceptVerbs("Get")]
        public IEnumerable<ItensLibDTO> getItensLiberacao()
        {
            return itens.getItensLib().AsEnumerable().ToList();
        }
    }