Cannot save to, or open documents from iCloud

Just noticed this morning that When I create a new Pages, Numbers, Keynote, PDF, etc. document from my 27 inch Retina iMac (running Catalina 10.15.1), I cannot save any of them to iCloud. For example a pages document presents the following error when trying to save to iCloud: "XXX.pages can't be opened right now. Pages couldn't read the file".

If I save the file to my iMac is saves just fine and I can open it just fine. But If I move the file to iCloud, and then try to open it from my iMac, I get this: " The document XXX.pages could not be opened". Also, when I move the documents from my iMac to iCloud, I can open the documents on iCloud just fine from my iOS devices.