Url request is working for GET but same URL not working for POST

New to APIs/Postman
1

I have a url request for GET and POST data but that url request is working for GET only please guide regarding this

http://localhost:8081/users

2

localhost:8081 indicates that you are running some local application.

It is hard to tell why a GET request works but a POST request not. Check the API documentation if you have one. Maybe you need to call a different endpoint.