In normal circumstances this shouldn't happen but in case if you encounter with 500 error after installing any plugin then there is no need to panic everything is secure and nothing has lost on your website.
500 error after plugin installation is because the system wasn't able to run Optimize Application task during plugin installation. To fix this go to website update URL http://www.yoursite.com/admin/update then click Run Update. After successful update your website will work fine.
Note: Remember to change yoursite.com with your website URL.
Still facing issue, feel free to create support ticket and we will debug the issue ASAP.