Website crashing soap error

Hi, when I activate your plugin my website crashes and I get the following error

Fatal error: Class ‘SoapClient’ not found in /home/canalalarm/public_html/active-vision.com/wp-content/plugins/credit-card-payments-for-woocommerce-with-cybersource/class-cybs-soapi-cc.php on line 12

How can I resolve this?