The rename error appears when the conversion can't be done, it's a generic error. The .config folder is available only in Linux OS (https://wiki.documentfoundation.org/UserProfile/en)
On https://www.phpdocx.com/documentation/conversion-plugin/common-problems-and-possible-errors you can read specific issues for each OS. As requested in our previous reply, please follow the steps explained on https://www.phpdocx.com/documentation/conversion-plugin/debugging-libreoffice (1st and 2nd in your case), are you able to do the conversion running LibreOffice directly as the first step details? does it work using PHP CLI mode? If the transformation can be done using the previous approaches (calling LibreOffice and PHP CLI), the problem comes from some missing permission or setup, what web server are you using?