404. That’s an error.

The requested URL /catalog/product_compare/add/product/3395/uenc/aHR0cDovL3d3dy50aHJvd21lYXBpbGxvdy5jb20vZ2lmdC1jYXJkLWdpZnQtY2VydGlmaWNhdGUuaHRtbA,,/ was not found on this server. That’s all we know.