title: Azure Function with Cosmos MongoDB integration not saving
body: <p>I have setup a Azure Function with a Azure Cosmos DB(document) output. The cosmos database is configured to be a MongoDB.
  And added the following simple code to try and add a new document:</p>
  
  <pre><code>module.exports = function (context, eventHubMessages) {
     context.bindings.document = {
     text : "Test data"
  }   
  context.done();
  };
  </code></pre>
  
  <p>When i test run i get success, but when i try to open the the collection using Studio 3T i get:</p>
  
  <pre><code>Query failed with error code 1 and error message 'Unknown server error occurred when processing this request.'
  </code></pre>
  
  <p>When i use the same code to write to a DocumentDB i get success and i can view data in Azure. Do you need to use a different API to save data to mongoDB?</p>