Hello Listening to Sounds in Colour,
Thank you for the details of the issue you are experiencing with Documents in the Cloud. I recommend following the steps in the section titled "Unable to upload documents" in the following article:
Thank you for using Apple Support Communities.
Hi Listening to Sounds in Colour,
Thank you for the additional information. Due to the nature of your issue or question you may find more information by using another one of Apple's support resources - https://getsupport.apple.com/GetproductgroupList.action
All the best,