Hi Daniel,
Thank you for your reply. I’m building a site for a client via a brand new installation of the Osmosis theme running WP 4.5.3.
I did start out with Easy Modal. Eventually I noticed the support docs Easy Modal links to are for a different plugin, Popup Maker. I discovered this after having spent over an hour trying to work through the documentation.
Realizing some of the shortcodes I was trying were for Popup Maker, I deactivated Easy Modal and installed Popup Maker. But still no luck, after having invested over an hour into learning that plugin and its documentation as well.
Afterward I installed PopUp by Supsystic and was able to get a popup running. This makes it seem less likely the issue was with the Osmosis theme, but doesn’t rule it out.
David