Massive Addons for WPBakery Page Builder

WPBakery does not load on edit page/post

You might be experiencing similar issue as Divi theme builder has got on SiteGround.

https://www.siteground.com/kb/divi-builder-timeout-warning/

Please add this code snippet into your .htaccess file:

<ifModule mod_substitute.c>
SubstituteMaxLineLength 10M
</ifModule>

If it will not help or you need assistance in implementing snippet - submit ticket.
Make sure to share inside support ticket: wp-admin access + FTP details.