From the information you have sent we have found the following line:
OK HOME environment variable issetfor the currentuserand has the following value: /home
If the HOME var in the web server:
<?php echo getenv("HOME");
is set to /home, then you need to create /home/.config folder with rw access. That seems the problem and the reason of the warning:
Warning The .config/libreoffice folder in the HOME folder must have rw access.
If needed, you can change the HOME folder instead of using the default one with the homeFolder option:
$docx->transformDocument('document.docx', 'output.pdf', 'libreoffice', array('homeFolder' => '/home/forge'));
or in config/phpdocxconfig.ini file (home_folder option).
Please also check the documentation available on the following page:
to debug it. As explained on the previous page, first check that LibreOffice can work standalone and then using PHP CLI mode.
If you send to contact[at]phpdocx.com SSH access to your server, the path where phpdocx is installed and a URL to test it using a web browser, the dev team will connect to check it.