404. That’s an error.

The requested URL /catalog/product_compare/add/product/2255/uenc/aHR0cDovL3d3dy50aHJvd21lYXBpbGxvdy5jb20vdGFwZXN0cnktcGlsbG93L2NhdC1kZWNvci9jYXQtYnJlZWQtcG9ydHJhaXRzLmh0bWw,/ was not found on this server. That’s all we know.