When I tested I got:
**Fatal error** : Uncaught TypeError: Argument 1 passed to Square\ApiHelper::appendUrlWithTemplateParameters() must be of the type string, null given, called in D:\vhosts\nac-issa.org\httpdocs\SquareEcom\vendor\square\square\src\SquareClient.php on line 304 and defined in D:\vhosts\nac-issa.org\httpdocs\SquareEcom\vendor\square\square\src\ApiHelper.php:47 Stack trace: #0 D:\vhosts\nac-issa.org\httpdocs\SquareEcom\vendor\square\square\src\SquareClient.php(304): Square\ApiHelper::appendUrlWithTemplateParameters() #1 D:\vhosts\nac-issa.org\httpdocs\SquareEcom\vendor\square\square\src\Apis\PaymentsApi.php(163): Square\SquareClient->getBaseUri() #2 D:\vhosts\nac-issa.org\httpdocs\SquareEcom\process-payment.php(56): Square\Apis\PaymentsApi->createPayment() #3 {main} thrown in **D:\vhosts\nac-issa.org\httpdocs\SquareEcom\vendor\square\square\src\ApiHelper.php** on line **47**
