Hi Stella!
I have been struggling with the same problem and solved it by switching from “Endnote online” to just “Endnote”.
I created a new Endnote library on my computer and wanted to copy citations from there to Word. However, when I searched for my citation with the “Insert citation” tool in Word, nothing came up and looked like the library was empty.
I then discovered that in the “Preferences/Applications” tab in Endnote ribbon in Word that my preferences were set to “online account” and not “local Endnote library”. Apparently I didn’t have any libraries in the Online account. After switching to “local Endnote library” in that menu I found all my citations.
Hope this helps!
Kamila