Using Libre 6.4, the version will not save any of my work. What solution should I try to fix the problem?

While I am on the LibreOffice website the program will save my work. When I’m not logged into the website none of my work is saved. When this is occurring I get messages like:
File could not be found.
File is Read Only.
File does not exist.
Don’t have access to save.

Difficult to believe. Please edit your question and add in it the information that you can copy from Menu/Help/About LibreOffice. and from where have you download the application.

And you also work with an operating system?