iCloud.com not allowing file uploads

I can't upload any local files to my iCloud Drive on iCloud.com. Tried multiple machines (mac and PC), all browsers, internet speed is fast (tried wired, wireless and hotspot) and I have 1.14 TB available so it's not a storage issue. Did all the apple server checks, all green, so assuming it's not on their end. I can't so much as upload a jpg, pdf, doc, NOTHING. I am out of ideas on what to do. I've been doing it this way for years (using drive as file storage/backup) and now all of a sudden it's not working.