Set image button not working, cannot replace menu image

Hey,

I am using the Menu Image plugin which was pretty good!
But recently when I want to change the image on the menu section, So when I click “Set image” button, there was nothing happened, so that I could not replace the menu image. It seems the “Set Image” button is malfunctional.
See reference link https://www.awesomescreenshot.com/video/2037230?key=2f541c3ece0b5217821bd22bd035cf04

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