HTTP calls to SharePoint

I am trying to do a post files to the SharePoint. For that I took help from below Link -

After registering the Add-In, I granted the permission and retrieved the Tenant ID through Postman.
After that I need to generate the Access Token, however I am getting below error -

{
“error”: “invalid_request”,
“error_description”: “AADSTS90002: Tenant f12a3f9e-37a5-4551-80f1-e93a20857154 not found. This may happen if there are no active subscriptions for the tenant. Check with your subscription administrator.\r\nTrace ID: 2d277d04-473c-4a21-aa5b-b3a66b740100\r\nCorrelation ID: 921acc97-f0cd-48d3-ae17-1cf88461c6d6\r\nTimestamp: 2018-03-01 10:02:30Z”,
“error_codes”: [
90002
],
“timestamp”: “2018-03-01 10:02:30Z”,
“trace_id”: “2d277d04-473c-4a21-aa5b-b3a66b740100”,
“correlation_id”: “921acc97-f0cd-48d3-ae17-1cf88461c6d6”
}

Can anyone help me on this, how to get the Access Token?

Were you able to simulate this with Postman 1st?

Did you follow the instruction of “Generate the Access Token” section?

Hi - @aleung , Thanks for reply. I tried that, but not working. I am kind of stuck.
I have followed below steps -

  1. I have Register as a Add-In in SharePoint.
  2. I have granted permission to the Add-In.
  3. Retrieved the Tenant ID through Postman (Get method).
  4. Tried to generate the access token using Postman, but getting below error -

“error”: “invalid_request”,
“error_description”: “AADSTS90002: Tenant f12a3f9e-37a5-4551-80f1-e93a20857154 not found. This may happen if there are no active subscriptions for the tenant. Check with your subscription administrator.\r\nTrace ID: 2d277d04-473c-4a21-aa5b-b3a66b740100\r\nCorrelation ID: 921acc97-f0cd-48d3-ae17-1cf88461c6d6\r\nTimestamp: 2018-03-01 10:02:30Z”,