permissions problem saving files to iCloud

I've been having a problem saving files to my iCloud. The file type doesn't seem to matter but I repeatedly and unpredictably get an error message that says that the file is locked. I usually have the option to Save Anyway, but about 50% of the time, I get another error after that says that I don't have the permissions to save to this location. 1) I'm the administrator on this account (and the only user) 2) I've changed the permissions on the folder and the enclosing folders and items so that "everyone" has read/write access. Still, the message says I don't have the credentials. This seems to happen with files that I've been working on for a while, no matter how recently I've saved them. I can't work out what the factors are that trigger this, but it's only happening with iCloud files.

Could it be batter/power related?

Screen time is turned off.

I have sufficient storage space remaining

any ideas?

thank you