Fatal error: Uncaught TypeError: Argument 1 passed to PingPong\src\Signature\Sign::isPingPongPay() must be of the type string, null given, called in /home/customer/www/apexellens.com/public_html/wp-content/plugins/woocommerce-pppay/vendor/PingPongPay/src/Notify/Notify.php on line 27 and defined in /home/customer/www/apexellens.com/public_html/wp-content/plugins/woocommerce-pppay/vendor/PingPongPay/src/Signature/Sign.php:50 Stack trace: #0 /home/customer/www/apexellens.com/public_html/wp-content/plugins/woocommerce-pppay/vendor/PingPongPay/src/Notify/Notify.php(27): PingPong\src\Signature\Sign->isPingPongPay(NULL) #1 /home/customer/www/apexellens.com/public_html/wp-content/plugins/woocommerce-pppay/wc-pppayupdate.php(101): PingPong\src\Notify\Notify::isPingPongPay(Object(PingPong\src\Core\PPConfigs), '') #2 /home/customer/www/apexellens.com/public_html/wp-content/themes/flatsome/templates/refundNotify.php(8): WC_Pppayupdate->refundNotify() #3 /home/customer/www/apexellens.com/public_html/wp-includes/template-loader.php(106 in /home/customer/www/apexellens.com/public_html/wp-content/plugins/woocommerce-pppay/vendor/PingPongPay/src/Signature/Sign.php on line 50