Shortcode not working in modal window

I have gallery & gallery Pro. I am using the galleries in modal windows. (to include text description with a slider on the same window). Tested with another plugin, the shortcode works (slider Pro). But with NGG, both the <img> link preview and the shortcode (from this page https://www.nextgen-gallery.com/nextgen-gallery-shortcodes/) doesn’t work. Any tips?

https://www.ads-software.com/plugins/nextgen-gallery/