The WordFence plugin can sometimes cause an issue with Visual Composer post-editing or downloading of assets. It majorly occurs due to a false trigger from WordFence to block such operations. To handle it add following values under: WordFence - All Options - Whitelisted URLs.
| URL | Param |
|---|---|
| /wp-admin/admin-ajax.php | request.body[vcv-content] |
| /wp-admin/admin-ajax.php | request.body[vcv-elements-css-data] |
| /wp-admin/admin-ajax.php | request.body[vcv-zip] |
| /wp-admin/admin-ajax.php | request.queryString[vcv-action] |
| /wp-admin/admin-ajax.php | request.queryString[vcv-admin-ajax] |
| /wp-admin/admin-ajax.php | request.queryString[vcv-zip] |
| /index.php | request.queryString[vcv-ajax] |