This issue is sometimes caused by the incompatibility between the latest versions of the WPBakery Plugin and the version of WordPress – it may have been caused with the newest WPBakery Plugin update.
To solve this, you can edit one of these two files located on your server:
The best way to make the change to these files is via FTP (file transfer protocol).
All it takes is to add this property for background-image:
After you’ve done this, you should simply clear cache and run the WPBakery once more through page options.