404. That’s an error.
The requested URL /catalog/product_compare/add/product/746/uenc/aHR0cDovL2pvc2VhbGRvLmNvbS5ici9hY2Vzc29yaW9zL2NoaW5lbG9zL2NoaW5lbG8tYmFieS10aXJhLWF6dWwtbWFyaW5oby0xLmh0bWw,/form_key/mZWjy6pfEOWlcbqe/
was not found on this server. That’s all we know.