I have visited:
And when I click on the galleries (eg. NextGEN Pro Masonry Galleries
Beautiful, responsive, masonry-style galleries. http://www.nextgen-gallery.com/nextgen-pro/#gallery/pro-masonry/357/0) I get a black screen with some circles going around and then they stop and when I select and copy on that black screen, it says:
Default Gallery Type Template
This is the default gallery type template, located in:
If you're seeing this, it's because the gallery type you selected has not provided a template of it's own.
Are you aware of this?