Before initiating currency exchange 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 Currency Exchange APIs is here.
Payment Services APIs support currency exchange payments (FX payments) which are used to buy/sell specific currency using ConnectPay provided currency exchange rate.