I’m getting this same issue. Same message:
“Fatal error: Theme CSS could not load after 20 sec. Please download the latest theme at https://galleria.io/customer”
I am not using a galleria theme. I am using a custom theme based on Sight by WP Shower.
Slickr Flickr worked really well before this. I would really like this issue resolved.
My Gallery is located here.
https://balletaustinguild.org/explore/photo-gallery/
