title: ServiceStack UserName should not be empty?
body: <p>I am sending the following POST request as per the documentation:</p>
  
  <pre><code>POST http://localhost:56049/auth/credentials?format=json HTTP/1.1
  User-Agent: Fiddler
  Host: localhost:56049
  Content-Length: 64
  
  {
      "UserName" : "admin",
      "Password" : "test",
      "RememberMe" : true
  }
  </code></pre>
  
  <p>However, it gives me an unexpected result:</p>
  
  <pre><code>{"responseStatus":{"errorCode":"ValidationException","message":"Validation failed: 
  \r\n -- 'User Name' should not be empty.\r\n -- 'Password' should not be empty.",
  "stackTrace":[...]
  </code></pre>
  
  <p>Why does it think my user name and password are empty?</p>
  
  <p>Ref. <a href="https://github.com/ServiceStack/ServiceStack/wiki/Authentication-and-authorization" rel="nofollow">https://github.com/ServiceStack/ServiceStack/wiki/Authentication-and-authorization</a></p>