Problem solved when i’ve moved my Wordpress installation to different server.

I don’t click in submenu, i just click on main “Digital publishing”M.

I've just tried this plugin on clean installation of WP 4.3.1, version 2.0.6 and 2.0.7, with no luck - after selecting "Digital publishing" in menu, i see "Failed. Could not perform action (get_settings)". I see it barely, because it's light grey on pink ).