3297888 - Messages sent to OpenConnector API failing in CPI with "An internal server error occured: HTTP operation failed invoking https://api.openconnectors<xyz> with statusCode: 400"

You have an iflow where the receiver HTTP channel connects to an OpenConnector API.
Messages for this iflow are failing with the error mentioned in the title.

You have also tested the same endpoint with the exact same payload and if you bypass the CPI tenant the messages are successfully delivered.

Checking the details of a failed message in CPI monitoring you can see that the this is the exact response that CPI gets back:
ResponseBody    {"requestId":"63ac5d4de4b0dea2f0c3aa57","message":"Stream content not provided."}     

• Cloud Integration
• SAP Integration Suite

Cloud Integration, SAP HCI, SAP CPI, SCPI, Integration Suite, tenant, IFlow, Integration Flow, OpenConnector, internal server error, failed invoking, statusCode: 400, Stream content not provided, form-data,  , KBA , LOD-HCI-PI-CON-HTP , HTTP Adapter , Problem