Before initiating standard payment, please ensure that your Access token has ob-ps and ob-ps:authz-nosca scope in it. In this flow, payments are carried out without explicit SCA/MFA authorization, therefore you need to have ob-ps:authz-nosca scope in the token.
Collection of Payment Services APIs is here.
Payment Services APIs support standard payments, such as Internal (between ConnectPay accounts), SEPA-SCT, SEPA-SCT-Inst and SWIFT payments.