O Auth 2.0 is not retrieving token , it does from the Postman but not from ServiceNow

[GD11]

I am doing REST Outbound integration from ServiceNow to Manage engine Service Desk for that Manage engine support Server based O Auth 2.0. I have configured it at our and wrote a scheduled job to get the token but it is not retriving any token it gives null response. if i click on the get OAuth token then it works fine but not through script or when i try to send request from REST POST. please help. sharing configuration attachments for reference. 

Grant type is authorization code. i have client id, secret, endpoint, scopes etc. but sitll note working.

@Ankur Bawiskar please help. stuck in this.

[GD11]

HI @Ankur Bawiskar  yes, there was issues at 3rd party end, when did the cofiguration correctly we started to get both Access and refresh tokens.