Missing Icons

Dear Developers,

Could you please advice why there is a missing icons on all icons of pricing tables like here:

1. https://www.ipreg.eu/национални-марки/;
2. https://www.ipreg.eu/%d0%bc%d0%b0%d1%80%d0%ba%d0%b8-%d0%bd%d0%b0-%d0%be%d0%b1%d1%89%d0%bd%d0%be%d1%81%d1%82%d1%82%d0%b0/
3.https://www.ipreg.eu/%d0%bc%d0%b5%d0%b6%d0%b4%d1%83%d0%bd%d0%b0%d1%80%d0%be%d0%b4%d0%bd%d0%b8-%d0%bc%d0%b0%d1%80%d0%ba%d0%b8/

and the rest from my site where I use the Pricing Table by Supsystic plugin shortcodes

Thank you in advance

The page I need help with: [log in to see the link]