We are using PO as our connection between CRM and C4C. Business partners and opportunities are loading to C4C, but we are getting 'Error in message header mapping; agent class is CL_BUPA_MDG_REPLICATE_BUPA' for business partners and 'Error in message header mapping; agent class is CL_APCRM_OPP_REPLICATE_IPA'. This is happening in our test C4C tenant where we are switching to use PO instead of PI. Our prod system with PI works fine. I am not seeing a difference in the payloads, except for sender/receivers. I have read in the C4C section some options, including checking the SAP Business Suite box, and that has already been done. Has anyone had encountered this and have a fix?