theme slider is not showing up

I recently purchased magazine theme from theme-forest.
Everything works fine and I made all modifications i need, but slider is not working.
As author said in the documentation he used flexslider plugin code for the theme slider.
I tried to contact him but it’s almost a week I wrote a message and still no answer. That’s why I decided to write here.
https://themeforest.net/item/today-info-news-magazine-wordpress-theme/6200502
This is the theme I purchased.
https://4motivi.com.sunshop.ge/ is a test site were I implemented it. I I set homepage and activated slider from theme options, but you can see that there is a blank space where the slider should be.

Help is much appreciated.

Thank you!