Hello,
You need to install and configure the conversion plugin correctly, it seems there's some missing rw access; the rename error is a generic problem when the document can't be generated. Please read the information available on:
https://www.phpdocx.com/documentation/conversion-plugin/conversion-plugin-installation-and-set-up
https://www.phpdocx.com/documentation/conversion-plugin/common-problems-and-possible-errors
https://www.phpdocx.com/documentation/conversion-plugin/debugging-libreoffice
to install, debug and solve the most common issues.
After config the conversion plugin, we recommend (as the debugging page explains), to test it using PHP CLI mode.
Regards.