404. That’s an error.
The requested URL /shop/index.php/catalog/product_compare/add/product/55653/uenc/aHR0cDovL3RlY2hub2ZveC5kZS9zaG9wL2luZGV4LnBocC9zYXQtcHJvZHVrdGUuaHRtbA,,/form_key/ZIcihyiMwAerkQQ1/
was not found on this server. That’s all we know.