Hi kasawer
Despite i uninstalled and reinstalled again extension using my account it still is retrieving this internal server error , you can try to
1) Downgrade your php version to 7.0 ( as test )
2) Upgrade your joomla version to latest released .
3) Solve jquery conflict ( Maybe some of your installed 3rd part extensions is not fully compatible )
These steps should fix your issues.
P.S.
I tested extension on my local installation and it works fine .
Hope it helps