title: AngularJS Mongoose findOne OK but save error :DocumentNotFoundError:
body: <p>On client.save() below, I have the following error (which is catch properly):</p>
  
  <p>DocumentNotFoundError: No document found for query "{ _id: '5bfbce595be7d1047c976e6b' }"</p>
  
  <pre><code>app.put('/api/client', function (req, res) {
      Client.findOne(new mongoose.Types.ObjectId(req.body._id)).then(client =&gt; {
              //This is OK, I can see client and its properties
              client.name = req.body.name;
              //This is OK, I can see the updated client and its properties
              client.save().then(test =&gt; {
                  console.log("ERR=" + err);
                  console.log(test);
              }).catch(err =&gt; console.log("ERR :" + err));
              res.json(client);
          });
  });
  </code></pre>
  
  <p>The model is as such:</p>
  
  <pre><code> mongoose.model('Client', {
      _id: {type: String, default: ''},
      name: {type: String, default: ''},
      creationDate: {type: Date, default: ''}
  });
  </code></pre>
  
  <p>How come the document is found on FindOne() and no more on save()?</p>