title: Cannot connect to Jupyter Notebook
body: <p>My environment:</p>
  <p>Windows 10 Professional
  Python 3.7.2
  virtualenv 16.4.3</p>
  <p>I created a new virtual environment with D:\Python37\Scripts\virualenv env</p>
  <p>Then I activated the virtual environment with env\Scripts\activate</p>
  <p>Then I installed jupyter with pip install --upgrade jupyter</p>
  <p>Finally, I started jupyter with jupyter notebook</p>
  <p>Everything starts up fine, and I create a new Python 3 notebook. Unfortunately, the notebook never connects to the server. I get the following error message in powershell</p>
  <p>Replacing stale connection: (token)</p>
  <p>In the browser, I get the following error message:</p>
  <p><em>&quot;A connection to the notebook server could not be established. The notebook will continue trying to reconnect. Check your network connection or notebook server configuration.&quot;</em></p>
  <p>My two prior virtual environments (with Jupyter) work fine. I've deleted .ipython, .jupyter, AppData\Roaming\jupyter, without any luck.</p>
  <p>I've cleared cookies from my browser and have tried a different browser. Nothing works.</p>
  <p>I've created two other virtual environments before, and both of those still work.</p>
  <p>All jupyter notebooks in the two working environments start up as untrusted, whereas the new environment starts up as trusted. I'm guessing that I clicked on something and now the notebook is looking to start up in a trusted fashion - which may require HTTPS.</p>
  <p>Where do I look to fix this problem?</p>