Error occurred in HTTP post request of "request-token" API

we are requesting temporary token to Jira from our application. For that we are using this URL: ‘https://*************.atlassian.net/plugins/servlet/oauth/request-token’
which parameter i need to pass in HTTP POST request.

Currently we are passing following parameter in POST method with body object.
“https://**************.atlassian.net/plugins/servlet/oauth/request-token”
{
“oauth_consumer_key”: “demo.123”,
“oauth_signature_method”: “RSA-SHA1”,
“oauth_version”: “1.0”,
“oauth_timestamp”: 1510575012,
“oauth_nonce”: “20171113121012485”,
“oauth_signature”: “MIIFDjBABgkqhkiG9sdfsdfsdfsdfsddsfiG9w0BBQwwDgQIUoPrp1OWPGcu6hqqKwl3Ugl54QY8MJcagXWNiFqnsaval3O+dbLJHEBayv0=”,
“oauth_callback”: “http://chrome-extension://sdfsdfsdfsdffsdfsdfsdfsdrngdkkpkaeofkbil/callback”
}

this way we always got following result,
“oauth_parameters_absent=oauth_consumer_key&oauth_problem=parameter_absent”
what we are missing here?

Please someone help me on this.