title: Uber API authentication is flaky
body: <p>I have been having a tough time trying to get authentication to reliably work.</p>
  
  <p>I am using node.js, express, passport to get an access token. I am able to construct a cURL URL from the commandline using the access token to access most resources. However, when I request the /v1/request endpoint I get an error:</p>
  
  
  
  <pre class="lang-none prettyprint-override"><code>{ message: 'Invalid OAuth 2.0 credentials provided.', 2015-05-05T02:15:35.457072+00:00 app[web.1]:   code: 'unauthorized' }
  </code></pre>
  
  <p>I have gotten the same cURL command to work before and then all of a sudden it stopped working (after updating it to use a new auth token).</p>
  
  <p>Would love some insight into ways to diagnose the issue - but auth seems to be working in general but not for the request endpoint. Here is the cURL URL I am using:</p>
  
  <pre class="lang-none prettyprint-override"><code>curl -X "POST" "https://sandbox-api.uber.com/v1/requests" -H "Content-Type: application/json" -H "Authorization: Bearer ACCESS_TOKEN_HERE" -d "{\"scope\":\"request\", \"start_longitude\":\"-122.31709\", \"start_latitude\":\"47.613940\",\"product_id\":\"6450cc0f-4d39-4473-8632-1e2c2049fefe\"}"
  </code></pre>