title: failed to serialize the response in Web API
body: <p>I was working on ASP.NET MVC web API, I'm having this error:</p>
  
  <blockquote>
    <p>The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.</p>
  </blockquote>
  
  <p>My controller is:</p>
  
  <pre><code>public Employee GetEmployees()
  {
      Employee employees = db.Employees.First();
      return employees;
  }
  </code></pre>
  
  <p>why I m getting this error?</p>