We return this API error code when the Card Security Code (CSC) is rejected or denied by the card-issuing bank. This error can be caused by: 

• The CSC code has failed several times, causing the card to be declined. The CSC may be incorrect. 
• In the request being sent to PayPal, the CSC code may contain extra or abnormal characters or spaces.

If you get this error while trying to process your credit card and all information is accurate, wait 24 hours and try again. Also: 

• Use a different card
• Look for extra or abnormal character spaces in the CSC code; delete any you find and resubmit the transaction

See the Developer Portal for a complete list of NVP/SOAP API error codes.