Fatal error: Uncaught Error: Call to undefined function curl_init() in /var/www/html/Sample_REST_PayPal_Commerce/create-token.php:35 Stack trace: #0 /var/www/html/Sample_REST_PayPal_Commerce/createClientToken.php(25): include() #1 /var/www/html/Sample_REST_PayPal_Commerce/doTransaction.php(23): include('...') #2 {main} thrown in /var/www/html/Sample_REST_PayPal_Commerce/create-token.php on line 35