I have PopUp working on my staging site. Everything's the same as my live site.
On my live site I went to create a new PopUp. I copied the content of the test site into the new PopUp. I hit save. Nothing is saved.
I end up with empty content. A list of popups that don't have a name, have no content, and show nothing.
I disabled all plugins and this is still behaving this way. Attached screenshots of before, after, etc.