The documentation for the INSUFFICIENT_FUNDS error code reads:
Buyer needs to add a valid funding instrument (e.g. credit card or bank account) to their PayPal account.
which seems to imply that this error code may only be returned if payer attempts to pay with a paypal account, and that no such code will be returned if a direct payment attempt is made (with a credit card).
Is my interpretation correct?
Direct credit card declines will will not give you a specific reason for the decline, but will return an error code, such as 15005, which translates to "This transaction cannot be processed." because "The transaction was declined by the issuing bank, not PayPal. The merchant should attempt another card." See DirectPayment Errors and Warnings for a complete list of Direct Payment error codes.
Incorrect.
It implies that, in the event that there are insufficient funds to support a payment transaction, and no valid funding instrument is assigned to the PayPal account, the 'INSUFFICIENT_FUNDS' error code will be presented.
Conversely it implies that, should a valid funding instrument exist, no such code would be generated.
To my knowledge, this error code is generated with the Payouts API if the PayPal account targeted has insufficient funds, regardless of the presence of any funding instrument.
