Hi,

Please, update the theme to the latest version firstly. To update the theme you need download the latest version on ThemeForest -> Downloads. Then just reupload new theme via Appearance -> Themes but install this plugin firstly https://wordpress.org/plugins/easy-theme-and-plugin-upgrades/
Also, we suggest you make a backup of all your files before any update.
Here is a video tutorial that should help you https://www.youtube.com/watch?v=KX2bMOv6TLU

Regards