@nayeemkhan302 If you’re getting a successful but empty response, I suspect it’s because you do not have permission to view any of the edX course catalog(s). I think that edX intends that API for internal use, or use only by approved partners. You’d need to contact edX and explain your use case, and get their approval to use the API. If they approve you, they would then grant your user permission to view the course catalog via that API.
In the meantime, you can test with the Open edX devstack or a custom installation of Open edX, where your admin user will have permission to view the course list.
Sorry, I don’t know of anything else to do. The edX support page indicates this is a very busy time, so I’d expect a delay in hearing back from them.
This particular forum is oriented around support for Open edX the platform, not edX the organization/website. Some edX employees do read it though; it would be helpful if you describe the value proposition you’re offering to edX if you want to increase your chances of someone seeing this and helping your request reach the right person.