After you incorporate hreflang tags, make certain they all level to indexable and crawlable pages. Check out which tags are causing the problems and rectify them by making certain the pages they’re pointing to are Stay.  Adding this code to every web page of your web site might be inconvenient https://addons.prestashop.com/nl/seo-zoekmachineoptimalisatie-vermelding/31857-automatische-google-rich-snippets-json-ld-opengraph-seo.html