Please update our theme with latest version to fix the issue. Follow the below steps to update the theme.
i) Download the theme from themeforest page.
ii) If you have made any custom changes in the code, please take a backup of it.
iii) Overwrite the updated theme files to the older theme files. Update the custom change that you had already.
iv) Go to wp-content/plugins/ through FTP.
v) Remove the folder designthemes-core-features/ from wp-content/plugins/
vi) Then Login to Dashboard > Appearance > Install Plugins. Install the Designthemes Core Features plugin. That’s it. Now you are updated to the latest version.