Unable to Assign Bank Account to Supplier via API – Clarification on PaymentPartyId and PaymentInstr

We are trying to assign a bank account to a supplier using the following endpoint:

fscmRestApi/resources/11.13.18.05/instrumentAssignments

We have successfully added the bank account using the appropriate API. However, when we attempt to assign the bank account to the supplier using the payload below, we encounter the following error:

"You can't create a bank account or credit card assignment without adding a payer or a payee party as the owner. (IBY-825844)"



API Request Payload:

{
"PaymentPartyId": 300000011502415,
"PaymentInstrumentId": 300000034224002,
"PaymentFlow": "DISBURSEMENTS",
"PaymentInstrumentType": "BANKACCOUNT",
"Intent": "Supplier"
}

Issue:

• We are unsure what values are expected for PaymentPartyId and PaymentInstrumentId in this context.

Kindly clarify: