fill municipality's combobox according to the selected state in Angular

Good morning,

I have a combobox of municipality that is loaded with the municipalities according to the state selected, I am bringing the data of an API done in C # as follows:

$http.post('views/sistema/sistemas/service.aspx/Municipio', {
    estado: form.estado || ''
    }).then(function (success) {
        let data = JSON.parse(success.data.d);
        $scope.data = data;
        $scope.isLoading = false;
        $scope.municipioDestino.aaData = data.map(it => {
            return {
                municipio: it.Municipio
            };
        });
    }, function (error) {
        $scope.isLoading = false;
});

but the error is returned:

  

Angular.js: 13236 Error: [ng: areq] Argument 'SystemController' is not a function, got undefined

What's wrong?