title: strange mongodb and mongoose error: not master and slaveOk=false error
body: <p>I'm getting a strange error in my node.js app</p>
  
  <p><code>not master and slaveOk=false code 13435</code></p>
  
  <p>I'm doing a findOne query using mongoose 4.0.2 hitting a mongodb 3.0.1.  The query was working earlier today.</p>
  
  <p>What is this error?  I'm running on mongohq on their standard per gb plan.</p>