Help need with OAuth 2.0

[KrithikaV]

Hi,

I am trying to get OAuth credentials set up to connect to a third party application using grant type : client_credentials.

When using Postman, I get the following response:

{
    "tokenType": "Bearer",
    "expiresIn": 86399,
    "authToken": "eyJhbGciO........EQ"
}

In the ServiceNow's OAuth 2.0 Credentials screen, when I click on 'Get OAuth Token' link, I get the following error: 

OAuth flow failed. Verify the configurations and try again. Error detail:invalid_request, Missing parameters: access_token

I tried to run the following in the background script:

var oAuthClient = new GlideOAuthClient();
var params = {grant_type:"client_credentials"}; 
var json = new global.JSON();
var text = json.encode(params);

var tokenResponse = oAuthClient.requestToken('My Provider Profile', text);
accessTokenResponse = tokenResponse.getBody();
gs.log('Token response: ' + JSON.parse(accessTokenResponse).authToken);

I get the following response:

OAuthProblemException{error='invalid_request', description='Missing parameters: access_token', uri='null', state='null', scope='null', redirectUri='null', responseStatus=0, parameters={}}
*** Script: Token response: eyJhbGciOiJIUzI1N.......AAgwpv0

The third party response does not contain the json parameter 'access_token' but has 'authToken' instead. I tried experimenting with the OAuth API Script : OAuthConsumerSupport by overriding the initiateCCTokenFlow method, but could not achieve anything useful.

Kindly help me with this.