404. That’s an error.
The requested URL /shop/index.php/catalog/product_compare/add/product/55852/uenc/aHR0cDovL3RlY2hub2ZveC5kZS9zaG9wL2luZGV4LnBocC9sdGUtZmlsdGVyLXJlLWZsdGUuaHRtbA,,/form_key/4ijECpxJG4N5kUEk/
was not found on this server. That’s all we know.