Authentication against Project Online reporting data (OData) using CSOM

Hello,

how to read a reporting data from Project Online using C#/CSOM (for example using console application or windows service)?

Authentication to SharePoint and Project Server Online basically works fine, but how to pass cloud-credentials (with onmicrosoft.com account) to the context of OData service?

When trying to read list of project names, the following exception occurs: "Access denied. You do not have permission to perform this action or access this resource."

string onlineURL = "https://nnn.sharepoint.com/sites/PWA";
using (ClientContext clientContext = new ClientContext(onlineURL))
{
  SecureString passWord = new SecureString();
  foreach (char c in "some pwd".ToCharArray()) passWord.AppendChar(c);

  clientContext.Credentials = new SharePointOnlineCredentials("user@nnn.onmicrosoft.com", passWord);

  projContext = new PS.ProjectContext(onlineURL);
  projContext.Credentials = clientContext.Credentials;
  projContext.Load(projContext.Projects);
  projContext.ExecuteQuery();
  foreach (PS.PublishedProject pubProj in projContext.Projects) // This one works fine
    this.textBox1.Text += pubProj.Name + "\r\n";


  ProjectOData.ReportingData context = new ProjectOData.ReportingData(new Uri(onlineURL + "/_api/ProjectData", UriKind.Absolute));
  context.Credentials = clientContext.Credentials; //CredentialCache.DefaultCredentials;
  var query = from p in context.Projects
    where p.ProjectStartDate > new DateTime(2013, 1, 1)
    orderby p.ProjectName
    select p;

    // This gives the following error:
    // Access denied. You do not have permission to perform this action or access this resource.
    foreach (ProjectOData.Project proj in query)
      this.textBox1.Text += proj.ProjectName + "\r\n";

}

REST queries like below works directly in IE browser (after logged in the PWA tenant) so am I miss something here?

https://nnn.sharepoint.com/sites/PWA/_api/ProjectData/Projects()?$filter=ProjectStartDate gt datetime'2013-01-01T00:00:00'&$orderby=ProjectName

or

https://nnn.sharepoint.com/sites/PWA/_api/ProjectData/Projects()?$orderby=ProjectName

Thanks,

Ville