Hello,
Once I’ve deactivated WooCommerce Stripe Gateway plugin, all works fine.
Seems you did not use the correct key, you have js error in the console http://prntscr.com/ozzq92
Follow Stripe docs https://stripe.com/docs/keys
If you have any other questions about stripe settings contact plugin author https://wordpress.org/support/plugin/woocommerce-gateway-stripe/
We are theme author and provide support for the theme, not for the third-party plugins, sorry.
Regards