can not move to “discount code” “E-mail” “settings”

I have a problem. When I open the WP panel of my site and go to -> Coupon Box -> Settings, I can’t go to the Coupon, Email, Email API, Assign, Design and Update tabs. What causes that problem?

Also, how can I translate emails? What is sent when someone asks for a coupon code?

I tried reinstalling the plugin, but it doesn’t work. I have already downloaded the data obtained and I would like to restore the plugin to its initial settings. Is that possible?