404. That’s an error.

The requested URL /catalog/product_compare/add/product/6739/uenc/aHR0cDovL3d3dy5idXlpbmdmdXJuaXR1cmUuY28udWsvaG9tZS1hY2Nlc3Nvcmllcw,,/form_key/U3BhWn1vmiLnjBbE/ was not found on this server. That’s all we know.