# 11607 (/api/nvp-soap/troubleshooting/11607)



Returns from the `DoExpressCheckoutPayment` API.

## Cause [#cause]

* A transaction has already been completed for this token. The request was previously processed, and the results were returned in the initial response.
* To prevent duplicate charges, PayPal marks the request as a duplicate and does not process it again. The buyer is not charged twice. Along with the error code, PayPal returns the result parameters of the original request for reference.

## Impact [#impact]

There is no impact on the original transaction. This is a decline on a second attempt at processing the same PayPal transaction.

## Resolution [#resolution]

* **No action required for prior payments:** If the request pertains to a payment that was already processed, no further action is required.
* **Submit new transaction requests correctly:** If this is a new transaction request, submit it with a different `MSGSUBID` or `INVOICE_ID` to avoid being flagged as a duplicate.
* **Subscribe to Instant Payment Notifications (IPNs) or webhooks:** Subscribe to [IPNs](/api/nvp-soap/ipn/) or [webhooks](/api/rest/webhooks/) to keep your system updated with PayPal's latest payment status, even if the initial API response is missed. This prevents duplicate transaction requests and ensures your system stays synchronized with PayPal.

## Upgrade [#upgrade]

The NVP/SOAP API integration method is deprecated. You can find more information about our latest integrations from the following resources:

* [REST APIs](/api/rest/)
* [PayPal Checkout](/api/rest/integration/orders-api/api-use-cases/standard/)
* [PayPal Developer homepage](/)

## Additional resources [#additional-resources]

* [Express checkout token](/api/nvp-soap/set-express-checkout-soap/)
* [NVP/SOAP integration](/archive/express-checkout)
* [NVP/SOAP error codes](/api/nvp-soap/errors/)

> **Info:** You can reach out for support at [paypal-techsupport.com](http://www.paypal-techsupport.com).