Problems with pop-up

So, i’ve installed the plugin and it works fine when I’m wrighting the posts, but it only manages to show the pop-up image when logged in! For the visitors, it does not show the photos, but it fades the page like it’s trying to load the gallery. The website is https://www.maoscriativas.com.br, i’m using the plugin within every post, but only discovered the issue today.

I’m using the very latest version of WP and the following plugins, all at the latest versions (wich I have disabled in order to see if there was any incompatibility with the gallery system, but t’was just a waste of time):

Front-End Editor 2.1.1 – https://scribu.net/wordpress/front-end-editor

FV Simpler SEO 1.6.12.1 – https://foliovision.com/seo-tools/wordpress/plugins/fv-all-in-one-seo-pack

Google XML Sitemaps 3.2.5 – https://www.arnebrachhold.de/redir/sitemap-home/

Grunion Contact Form 2.2 – https://automattic.com/#

jQuery Lightbox For Native Galleries 3.3.3 – https://www.viper007bond.com/wordpress-plugins/jquery-lightbox-for-native-galleries/

SEO Rank Reporter 1.1 – https://www.kwista.com/

TinyMCE Advanced 3.4.2.1 – https://www.laptoptips.ca/projects/tinymce-advanced/

Vibe SEO Pack 1.2 – https://www.vibethemes.com/wordpress-plugins/vibe-seo-pack-wordpress-plugin/

WordPress Meta Keywords 1.2 – https://www.destio.de/tools/wp-meta-keywords/

WordPress SEO-Rank 1.0 – https://nexxuz.com/wordpress-seo-rank-plugin.html

WP-PageNavi 2.74 – https://www.ads-software.com/extend/plugins/wp-pagenavi/