Plugin site: https://wordpress.org/plugins/newsletter/
Page that use the shortcode [newsletter]: http://gemix2.pe.hu/newsletter/
failed Pop-up: https://ibb.co/9NpxsF1
I now encounter another problem. All the static blocks cannot be viewed. It shows “page not found”. This is the same one I used for newsletter popup. http://gemix2.pe.hu/staticblocks/newsletter-30-09-2020/
