Problem Saving Docs In Ms Word

I've just started to have a problem in saving new documents in Microsoft Word 365.

When I try to save one I'm receiving an error message which says, "name of the file, File not found. Check the filename and try again". It shouldn't be saying that. Of course, it won't find the file because I'm trying to save a new file, not open an existing one.

Has anyone encountered this problem? How can I discover its cause? What can I do to rectify it?

I attach a screenshot showing an example of the message I receive.

 

Check this out: https://www.tenforums.com/microsoft-office-365/112180-file-not-found-when-doing-save.html