Fatal error: Uncaught TypeError: Argument 1 passed to ExchangeRate::convertAmount() must be of the type string, null given, called in /var/www/my.payhalal.net/controllers/api/pay.controller.php on line 384 and defined in /var/www/api-merchant.payhalal.my/_classes/ExchangeRate.php:16 Stack trace: #0 /var/www/my.payhalal.net/controllers/api/pay.controller.php(384): ExchangeRate->convertAmount(NULL, NULL) #1 /var/www/my.payhalal.net/index.php(66): pay->__construct() #2 {main} thrown in /var/www/api-merchant.payhalal.my/_classes/ExchangeRate.php on line 16