i use alerts for making successful info message but error appears. what  is wrong?

$('.set-id-address').on('click', function (e) {

e.preventDefault();
var id_address = $(this).data('id_address');
var id = $(this).data('id');

$.ajax({
url: '/addresses/set-id-address',
data: {id_address: id_address, id: id},
type: 'get',
success: function (res) {
 toastr.success(res);
},

error: function () {
alert('error')
}
});
this.disabled = true;
});