Oauth1.0a - Request token URL "http://localhost:8080/plugins/servlet/oauth/request-token" not workin

[ranga_chinnaswamy]

I have downloaded the Jira Server to my local system to connect a third party application with Jira Server. The local server is up and running in the URL below for reference.

 http://localhost:8080/secure/Dashboard.jspa

I have run the request-token from postman, getting error. Please find the screenshots for your reference. I have given the request URL as 

http://localhost:8080/plugins/servlet/oauth/request-token

Header parameteters as 

Content-Type : application/json

CONSUMER-KEY : Oauthkey ( which is the hard coded value given while creating the Application link in Jira)

PRIVATE-KEY : Generated from OPENSSL

Please let me know if I do anything wrong.