I am new to PayPal integration coding and getting this error response by the PayPal API:
"10001 Internal Error"
..and here is what I had sent to paypal at "https://api-3t.sandbox.paypal.com/nvp":
METHOD=DoExpressCheckoutPayment&TOKEN=XY-37X97072&PAYERID=B7JHY6QVBX&PAYMENTREQUEST_0_AMT=9.9&PAYMENTREQUEST_0_CURRENCYCODE=USD&PAYMENTREQUEST_0_PAYMENTACTION=Sale&USER=info_api1.abcd12345.com&PWD=YJHT2GXEL8H2L&SIGNATURE=NIXVrzp399rJ6uMui6ZfAxt&SUBJECT=NewOrder&VERSION=124.0&BUTTONSOURCE=PP-ECWizard
Can someone see what I am doing wrong and please help?