CSOMUnknownUser error on working with draft project in Project Server 2013 CSOM
<p>I'm trying to work with Project Server 2013 CSOM and I can authenticate, read any information, create new project and so, but I have problem with draft projects, in any way when I want to execute query on draft project I receive error message <code>CSOMUnknownUser</code> and any thing.
In my search's I didn't get special information about this error and<br>
here is part of my codes:</p>

<pre><code>context = GetContext(pwaInstanceUrl);

// Retrieve publish project named "New Project"
// if you know the Guid of project, you can just call context.Projects.GetByGuid()
csom.PublishedProject project = GetProjectByName(projectName, context);
if(project == null)
   {
      Console.WriteLine("Failed to retrieve expected data, make sure you set up server data right. Press any key to continue....");
                return;
   }

csom.DraftProject draft = project.CheckOut();

   // Retrieve project along with tasks &amp; resources
context.Load(draft, p =&gt; p.StartDate,                                                         
                                    p =&gt; p.Description);                                                      
context.Load(draft.Tasks, dt =&gt; dt.Where(t =&gt; t.Name == taskName));                           
context.Load(draft.Assignments, da =&gt; da.Where(a =&gt; a.Task.Name == taskName &amp;&amp;                
                                                                    a.Resource.Name == localResourceName));   
context.Load(draft.ProjectResources, dp =&gt; dp.Where(r =&gt; r.Name == localResourceName));       
context.ExecuteQuery();
</code></pre>

<p>I receive error on last line <code>context.ExecuteQuery()</code></p>