On the local application that consumes the API, turn up the log level of REST Consume up to TRACE. That will log the request and response, so you can see what is being sent by your application and what is being received.
You could also put a breakpoint on the REST service microflow that exposes the data and see what happens when (or if) the service is being called.
Good luck!
Thanks Robert and Ganesh, I figure out the problem I used the URL for swagger instead of using API end point. Thanks every one.