I've used the desktop app dozens of times to transfer or share documents, but suddenly, my recipient is getting an error message that says the zip file is invalid.
The folder I'm trying to share is the one at top. As you can see, the blue icon looks different than the others, but I'm not sure why or what it means. Thanks for any help.

Device (iMac)
Operating System/Browser (if using the web)
(Sequoia 15.5, Firefox)