title: Beats can't send data suddenly to ES with errors pop up
body: <p>I am using ES 5.0, Kibana 5.0 alpha4 and various beats to send data to ES. Everything runs fine and smooth at first. However, after a day, the beats suddenly cannot send the beats to the ES. I have been using different beats, including winlogbeat, metribeats, etc. All of them suddenly stop working.</p>
  
  <p>Error is as shown</p>
  
  <pre><code>2016/07/16 15:22:15.259659 single.go:130: INFO Connecting error publishing events (retrying): 401 Unauthorized
  2016/07/16 15:22:15.259695 single.go:145: INFO send fail
  </code></pre>
  
  <p>What would be the issue?</p>