We will return this NVP/SOAP API error code when the Express Checkout token has expired. By default, the token is only valid for three hours.
The buyer will need to re-initiate the checkout process. It subsequently creates a new checkout session with a new token for which the buyer will approve.
To request having the token expiry time frame extended, please contact Business Support.
See the Developer Portal for a complete list of NVP/SOAP API error codes.