images on multisite

Hi, I just purchased the paid version of Easy Restaurant Menu Manager and installed it on my multisite network. I’ve activated on the site that needs it, http://www.hop-n-grape.com (network url http://writecraftwordpress/hopngrape/. I was able to create a menu, and add categories, BUT when I click the upload image button nothing happens, and the item icon images are broken. Any tricks or tips on using this plugin on a multisite network?

https://ww.wp.xz.cn/plugins/easy-restaurant-menu-manager/