" GTM no-script code not found: both lacking or not in " I check out to include the script inside the header.tpl but there's no part. Update: Problem was solved. I just use Yet another addon and customise hook to make it happen. Many thanks Ali Edited November 21, 2018 https://addons.prestashop.com/fr/seo-referencement-naturel/30904-balises-hreflang-automatiques-et-balises-canoniques-seo.html