404. That’s an error.

The requested URL /catalog/product_compare/add/product/1616/uenc/aHR0cDovL3d3dy5sZW9uc2FmZXR5cHJvZHVjdHMuY29tL3BlcnNvbmFsLXNhZmV0eS9wZXJzb25hbC1hbGFybXMuaHRtbA,,/form_key/3pD5z8Z1yRx3nmh6/ was not found on this server. That’s all we know.