Hey, man!
Thanks for the review. I just tested it on WordPress 4.8 and the plugin works fine.
Looks like you are having a problem at your end.
I can understand that having an issue like this could be frustrating. Let me assure you that the plugin is working fine on a new WordPress install with the default theme and no other plugins installed.
?? Try deactivating all plugins. If that resolves the issue, reactivate each one individually until you find the cause.
?? If that does not resolve the issue, try switching to the default theme for your version of WordPress to rule-out a theme-specific issue (theme functions can interfere like plugins).