Server-to-Server authentication scenarios error

Hi All,

I am working on S2S sample provided by Microsoft using the below link "https://msdn.microsoft.com/en-us/library/mt790168.aspx"

I was able to perform the steps provided for "Use Multi-Tenant Server-to-server authentication" 

but whenever I click on WhoAmI Request

I am getting the below error

{"The HTTP request is unauthorized with client authentication scheme 'Anonymous'. 
The authentication header received from the server was 'Bearer authorization_uri=https://login.windows.net/ea60d0a0-f3ed-48a2-a662-a32b6ca65382/oauth2/authorize, resource_id=https://india2032.crm.dynamics.com/'."}

Note:

1. My CRM instance is on Dynamics 365 and it is trial.

2.  I have separate Azure subscription and I have added the dynamics 365 Tenant active Directory to my Azure instance.

Thanks & regards

Subhash Mahato