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?
&SUBJECT=NewOrder Get rid of this, that's not a valid payee recipient
Why are you using the very old Classic API instead of the current v2/checkout/orders? See: https://developer.paypal.com/docs/business/checkout/server-side-api-calls/#server-side-api-calls
You'll need two routes on your server that return JSON, one for 'Create an Order' and one for 'Capture Order'. Then pair those two routes with the following approval flow: https://developer.paypal.com/demo/checkout/#/pattern/server