Need help to generate Jira Access token

I am refering this link https://developer.atlassian.com/server/jira/platform/oauth/ to generate Access Token.

The access token is used to authorize Github to Jira server

I am able to create Access token.
But in the last step Step 4: Make a request:

when i do a test I am getting below
error:

com.google.api.client.http.HttpResponseException: 401 Unauthorize

Could you please help here to solve the problem?

Thanks
Jeetendra