Error when using IBY_DISBURSEMENT_SETUP_PUB.Create_External_Payee() API

I am EBS R12.2.10 and trying to default supplier payment method using API
IBY_DISBURSEMENT_SETUP_PUB.Create_External_Payee(); 

I am getting error

Error Message from table type : IBY_DUPLICATE_EXT_PAYEE

I am trying to setup payment method at supplier level

  mo_global.init('AR');

    fnd_global.apps_initialize (user_id        => g_user_id,

                                  resp_id        => g_resp_id,

                                  resp_appl_id   => g_resp_appl_id);

--party_id from ap_suppliers table for the vendor_id

l_ext_payee_rec.Payee_Party_Id := 6061629;

l_ext_payee_rec.payment_function := 'PAYABLES_DISB';

l_ext_payee_rec.Exclusive_Pay_Flag := 'N';