Latest version of woocommerce is not working with this plugin. Please check this once.
simplexml_load_string function is not working, which is written in woocommerce_slide_out_cart.php ->line no. 190.
Here is the warning & error messages:
**_Warning: simplexml_load_string(): Entity: line 1: parser error : Entity 'ldquo' not defined in /var/www/html/project-folder/wp-content/plugins/horizontal-slide-out-cart-for-woocommerce-master/woocommerce-slide-out-cart.php on line 190
Fatal error: Uncaught Error: Call to a member function attributes() on boolean in /var/www/html/project-folder/wp-content/plugins/horizontal-slide-out-cart-for-woocommerce-master/woocommerce-slide-out-cart.php:192_**
Please take a look into this issue once. Let me know if you need any more details.
Regards
Pratyay.