Why did I get API error code 10419?
PayPal returned API error code 10419 - Indicates that the Express Checkout PayerID is missing in the transaction.
Cause
The PayerID value referenced is invalid or missing.
Solution
To obtain and specify the PayerID, see How do I create a one-time payment with Express Checkout?
Note: See the Developer Portal for a complete list of NVP/SOAP API error codes.