You should contact the theme author for free support
I did two hours ago but I got no reply
The author’s support says that they can take 2 business days to reply https://themeforest.net/item/impreza-retina-responsive-wordpress-theme/6434280/support
That’s why I posted here, thought somebody faced this before so I can get fast help.
You can set the WP_DEBUG to true and refresh that section from the theme panel. Maybe some errors will be shown there.