Search engines like google don’t index 4XX pages since they don’t function. Therefore, they’ll ignore any canonical tags pointing to this kind of pages and sometimes find yourself indexing the incorrect (non-canonical) Model of the page. che voi sappiate c'e' modo di integrare nel codice di prestashop il tag for each https://socialbuzzmaster.com/story4385290/5-simple-statements-about-tags-autom%C3%A1ticas-hreflang-e-tags-can%C3%B4nicas-seo-explained