Note that If the shop has by now been indexed by Google or any other search engine, it might consider a while for the changes to seem from the search results... you might have to Wait and see! Most of the time, we suggest not to the touch these fields https://www.presta-addons-modules.com/en/seo/prestashop-seo-automatic-hreflang-tags-canonical-tags-on-all-pages.html