Unable to create a new session using Selenium JSON Script

Question

I installed Selenium Standalone server and run it on my terminal. Selenium Jar file was launched. I navigated through localhost:4444 and choose selenium console. Further, when I tried creating a new session using firefox driver, It says - unable to create a new session- Connection refused. My geckodriver and mozilla selenium server is saved in a same directory.
KIndly help me out.