Why did I get API error code 10602?
PayPal returned API error code 10602 - Authorization completed.
Cause
The authorization has already been completed. The following API calls can produce this error: DoAuthorization, DoCapture, DoReauthorization, and DoVoid.
Solution
Use the GetTransactionDetails API call to check the status of the transaction. If your authorization is pending, you can try to capture it.
For help resolving this issue or others, visit PayPal's Contact Customer Service page.
See also:
GetTransactionDetails API Operation (NVP and SOAP)
See the Developer Portal for a complete list of NVP/SOAP API error codes.