Please make sure that you are using the below latest version of the theme.
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This can be due to plugin conflict on your site so please try temporarily deactivating all plugins except Unyson, Redux framework, Yoast SEO, and WpBakery page builder plugins and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.
If you still face the issue then would you mind if I log in to your site and do quick troubleshooting? If this is ok then could you please temporarily create an admin user account and share me the account login details privately by adding them in the box having text “Enter your private content here (only you and forum moderators will be able to see it)”?