404. That’s an error.
The requested URL /catalog/product_compare/add/product/4268/uenc/aHR0cHM6Ly9zaW1wbGEuYXo6ODA4MC9idW5kbGUtdW5pLXBhY2stc2gyMDAtYmFieXNlbi1jb3Rzd2FiLmh0bWw,/form_key/ubbfMyBWJv4zFUuP/
was not found on this server. That’s all we know.