You've initiated a REST-based API call to an SDN controller and received a 500 status code. What will most likely fix the problem?

The most likely course of action is to restart the REST-based service, since a 500 status code means that there is an internal server error. If a 400 status code was returned, it would most likely be the formatting of your request. If a 403 status code was returned, it would suggest that you have not authenticated to the software-defined network (SDN) controller or you are not authorized to access the API. A 200 status code means that everything was successful and the request is OK.