Robertoss on "[Plugin: Polylang] After activating the plugin, the site becomes unavailable"

I have a theme
<<Book Your Travel>>http://themeforest.net/item/book-your-travel-online-booking-wordpress-theme/5632266 /and tried to install the plugin <Polylang >but after activating the site becomes unavailable can help me.My website.

https://wordpress.org/plugins/polylang/