ProjectServer 2013 REST APIs with Windows Azure Access Token - azure

Question

I'm trying to use Project Server 2013 REST APIs with Windows Azure access tokens but getting GeneralSecurityAccessDenied error.
I have register my app in Azure AD on the Management Portal to get client_id, redirectUri.
The permissions to the application are “Office 365 SharePoint Online” and “Windows Azure Active Directory”.
I’m calling the authorization endpoint in the following URL, is this correct?
https://login.windows.net/common/oauth2/authorize?response_type=code&client_id= &redirect_uri=&resource=https://.sharepoint.com
Then I’m calling token endpoint URL
https://login.windows.net/common/oauth2/token with the following parameters
grant_type is authorization_code
code is “Access Code Returned from the first call”
redirect_uri is <MY URL>
resource is https://<mytestdomain>.sharepoint.com
This gives me Access Token and Refresh Token, but when I use the Access Token to do something it gives me the error “GeneralSecurityAccessDenied”
My POST request is
https:// <mytestdomain>.sharepoint.com/sites/pwa/_api/ProjectServer/Projects/Add
Authorization is Bearer <Access Token>
Content-Type is application/json;odata=verbose
The request body is
{
'parameters' : {
'Name':My Test ',
'Description': Test Project',
'Start':'1/28/2015'
}
}
The Error response is follows.
{
"error": {
"code": "20010, Microsoft.ProjectServer.PJClientCallableException",
"message": {
"lang": "en-US",
"value": "GeneralSecurityAccessDenied"
}
}
}