title: unable to open jupyter(ipython) notebook on browser
body: <p>I'm using <code>python3.5</code> and <code>jupyter 4.0.6</code>. I launched the <code>jupyter notebook</code>, and get the following output:</p>
  
  <pre><code>[I 21:47:27.021 NotebookApp] Serving notebooks from local directory: /home/nitrous
  [I 21:47:27.021 NotebookApp] 0 active kernels
  [I 21:47:27.021 NotebookApp] The Jupyter Notebook is running at: http://localhost:8888/
  [I 21:47:27.022 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
  [W 21:47:27.023 NotebookApp] No web browser found: could not locate runnable browser.
  </code></pre>
  
  <p>on my <code>firefox</code> browser, I typed the specified localhost url: <code>http://localhost:8888/</code> but I get <code>unable to connect</code> error message. What am I missing? is the hint of the problem on this line: </p>
  
  <pre><code>[W 21:47:27.023 NotebookApp] No web browser found: could not locate runnable browser.
  </code></pre>
  
  <p>it is my first time using the notebook. I tried to put the below code in the <code>jupyter_notebook_config.py</code> file but to no avail:</p>
  
  <pre><code>c.NotebookApp.open_browser = True
  c.NotebookApp.browser = 'firefox'
  </code></pre>
  
  <p>it also says <code>0 active kernels</code>. is that a problem? </p>