The problem was with the plugin WP Super Cache. The updated version 1.12.4 fixed the issue.
@all, thanks for your help. The problem was with the plugin WP Super Cache. The updated version 1.12.4 fixed the issue.
Hi @ckadenge,
Thanks for your advice. The shop already uses storefront as theme. After the weekend (shop is currently active and needed), I’ll try the deactivation again on a staging site.