OAuth 2 Resource Owner Password Credentials grant in ACS

This grant type is not supported in ACS. That makes sense, because ACS has no user database meant for end user credentials, and is unable to autheticate end users.

Example request:

POST /v2/OAuth2-13 HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Accept: application/json
Host: xxxx.accesscontrol.windows.net
Content-Length: 93

grant_type=password&scope=http%3A%2F%2Fmysite.com&username=abc&password=xyz

Response:

HTTP/1.1 400 Bad Request

{ "error":"unsupported_grant_type",
  "error_description":"ACS70003: The access grant \u0027password\u0027 is not supported. }