title: NodeJS: Uploading PDF to S3 via Knox; putFile returns 505
body: <p>I'm trying to upload a PDF to an S3 bucket using the Knox library, but I keep getting 505 errors and the PDFs won't save. My code:</p>
  
  <pre><code>// all of this works well
  var knox = require('knox');
  var client = knox.createClient(require('../path/to/config.js').knox);
  
  client.putFile('tmp/file', '/prefix/key',
    function(err, res) {
      if (err) {
        console.log("Error PUTing file in S3:", err);
      }
  
      console.log("S3 RESPONSE:", res.statusCode); // returns 505
    }
  );
  </code></pre>
  
  <p>Anyone have any insight into what I'm doing wrong? I've also tried setting my own headers using client.put(..), but I got the same 505 response.</p>