Hello,
I’m afraid that we are not able to fix this issue from our side. Point is that your server log displays error related to server configuration
[:error] [pid 3608926:tid 47462813312768] [client 175.107.223.143:38305] [client 175.107.223.143] ModSecurity: Warning. Matched phrase "wp-config.php" at REQUEST_FILENAME. [file "/etc/apache2/conf.d/modsec_vendor_configs/OWASP3/rules/REQUEST-930-APPLICATION-ATTACK-LFI.conf"]
etc and server support should take a closer look at this issue in the first case. As I understand they just don’t want to have deal with this and check the server configuration. Server log does not have information about errors in plugin or theme files but in server config files.
If you want that WPBakery support also takes a look at this you need to buy an individual plugin license, unfortunately, and require direct support from the plugin author.
Regards