404. That’s an error.
The requested URL /catalog/product_compare/add/product/25994/uenc/aHR0cHM6Ly93d3cuYnV5Zm9vdGJhbGxzdHVmZi5jb20vdHJhaW5pbmctZmllbGQtZXF1aXBtZW50L2Zvb3RiYWxscy5odG1s/form_key/KZY4tarTeQtjVZa6/
was not found on this server. That’s all we know.