Problem running Dash in Jupyter Lab

Hello everybody,

I wonder if anyone has any idea why my example app is not working in Jupyterlab. I have the jupyterlab-dash extension installed, and enabled. However, I can’t get the example app in the getting_started.ipynb document to work.

When I run it, I get an error in the last command: app.run_server(mode="jupyterlab")

ConnectionError: HTTPConnectionPool(host='', port=8050): Max retries exceeded with url: /_alive_0d62ebef-336d-4fa8-9aab-d4cd3fa9a55b (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x11962b790>: Failed to establish a new connection: [Errno 61] Connection refused')) 

I tried running instead: app.run_server(mode="inline"), as well as app.run_server(). I keep getting the same error.

If anyone has any idea why this is happening, I would much appreciate some feedback.