How to get WPBakery Page Builder 6.2 to open correctly and not remove blocks?

Question

Web development

The WPBakery Page Builder 6.2 constructor does not open on the front-end (hangs on the process of showing the plugin logo), and on the back-end deletes blocks when saving changes. Downloading a previous version does not help. Disabling other plugins too. Nobody knows where to dig? The site is here .

Chrome console shows the following errors:

Uncaught TypeError: window.vc.frame_window.jQuery is not a function
    at window.vc.ShortcodesBuilder.buildFromContent (frontend-editor.min.js?ver=6.1:10)
    at Object.vc.build (frontend-editor.min.js?ver=6.1:10)
    at frontend-editor.min.js?ver=6.1:10

along the path /wp-content/plugins/js_composer/assets/js/dist/frontend-editor.min.js?ver=6.1

Answer 1

It is necessary to dig exactly in one place. In support of WPBakery Page Builder https://wpbakery.com/features/support/?v=9025a1ae8c64
Because along with the sale of the plugin, they assume the obligations of support