Registration of MySQL records with NodeJS (Backend) that does not enter "Success" and hangs. That could be happening?

I expose the code to see if someone can help me

HTML code with the button that calls the function:

<div  id="btn_crearcurs" class="btn_curs">
     <a class="btn btn-warning btn-lg btn-block" ng-click="crearCursos()">Crear cursos i aules</a>
</div>

AngularJS driver that passes the data to NodeJS:

$scope.crearCursos = function () {
     $scope.loader.loading = true;
     var lista = $scope.selected;
     if (lista.length <1)
     {
         alert("No ha seleccionat ningún curs.");
     }
     else
     {
         $scope.loader.loading = true;
         $http.post("/cursos/cursosC", {
             'seleccio' : $scope.selected,
             'ip' : $rootScope.mi_ip,
             'usu' : $rootScope.idUsu,
             'cif' : $rootScope.cifAssoc
         })
         .success(function (data, status, headers, config) {
             $scope.loader.loading = false;                    
             $state.go("private.adminsAssoccurs");
         })
         .error(function (error) {
             $scope.loader.loading = false;
             console.log(error);
         });                
         $state.go("private.adminsAssoccurs");
     }
};

Code (path) in NodeJS that inserts the records in the MySQL database:

app.post('/cursos/cursosC', function (req, res) {
    var seleccio = req.body.seleccio;
    var ip = req.body.ip;
    var usuari = req.body.usu;
    var cif = req.body.cif;
    var valores = preparaMatriz(seleccio, ip, usuari, cif);
    db.get().query("INSERT INTO cursoscentres (cifAssocCursAssoc, cursAssoc, descripcioCursAssoc, aulaCursAssoc, datacreacioCursAssoc, ipcreacioCursAssoc, usuaricreacioCursAssoc, altaCursAssoc) VALUES ?", [valores], function (err, result) {
        if (err) {
            var data = {"error": 1, "err": err};
            return data;
        } else {
            var data = {"error": 0};
            //console.log(data);
            return data;
        }
    });
});