This is what I'm sending to https://api-3t.sandbox.paypal.com/nvp: VERSION = 65.0 SIGNATURE = AFcWxV21C7fd0v3bYYYRCpSSRl31AxdW2pQp.tWHTjGNcHflR-LJhJ0t USER = seller_1283487740_biz_api1.gmail.com PWD = 1283487748 AMOUNT = 50.00 CREDITCARDTYPE = Visa ACCT = 4031477440127509 EXPDATE = 12/2015 CVV2 =123 IPADDRESS = 127.0.0.1 METHOD = DoDirectPayment I can GetBalance, I can produce other errors when I intentionally send something wrong, but DoDirectPayment or DoAuthorization returns this: TIMESTAMP = 2010-12-24T03:35:10Z CORRELATIONID = 2ca329fdbe3c0 ACK = Failure L_ERRORCODE0 = 10001 L_SHORTMESSAGE0 = Internal Error L_LONGMESSAGE0 = Timeout processing request