Consume WebAPI by AngularJs

I have a POST method in the WebAPI, and this is the Api RoutePrefix, the Route of the POST method and Cors is enabled.

[RoutePrefix("api/v1/crm")]
[EnableCors(origins: "*", headers: "*", methods: "*")]
public class EmpresaParticipanteController : ApiController
{
    private SigCodeFirst db = new SigCodeFirst();

    [HttpPost]
    [Route("registros")]
    public HttpResponseMessage PostRegistro(EmpresaParticipante empresaParticipante)
    {
        if (empresaParticipante == null)
            return Request.CreateResponse(HttpStatusCode.BadRequest);

        try
        {
            db.EmpresaParticipante.Add(empresaParticipante);
            db.SaveChanges();

            var resultado = empresaParticipante;
            return Request.CreateResponse(HttpStatusCode.Created, resultado);
        }
        catch (System.Exception)
        {
            return Request.CreateResponse(HttpStatusCode.InternalServerError, "Falha ao incluir registro.");
        }
    }
}

In AngularJs, the script is as follows:

var crmApp = angular.module("Crm", []);
crmApp.controller("CrmCtrl", function ($scope, $http) {

   $scope.adicionarRegistro = function (empresaParticipante) {
       $http.post("http://grupo.ddns.net/GRUPO/api/v1/crm/registros", empresaParticipante).success(function (data) {
           delete $scope.empresaParticipante;
           $scope.novoCrmForm.$setPristine();
           console.log(empresaParticipante);
           carregarRegistros();
       });
   };
});

In the URI it looks like this: link

Domain: http://grupo.ddns.net

Directory inside server (where code is published): GRUPO/

RoutePrefix (API): api/v1/crm/

Route (POST method): registros

The problem is:

When I put this application on the net, it has a path error not found (404) in this URI above.

Given this structure of the directory server, and the API Routes, how should I mount the URI to work on the net? Or, should I do something different to work better?

Remembering that the server is in the company and as seen in the domain above, it has no fixed IP.