title: airflow webserver started but UI doesn't show in browser
body: <p>I'm trying to use <code>airflow</code> .</p>
  
  <p>I want to take a local test of the dags I wrote. I'm on windows so I decided to install ubuntu WLS following this bief tutorial <a href="https://coding-stream-of-consciousness.com/2018/11/06/apache-airflow-windows-10-install-ubuntu/" rel="noreferrer">https://coding-stream-of-consciousness.com/2018/11/06/apache-airflow-windows-10-install-ubuntu/</a>.
  Everything seems fine.</p>
  
  <p>I started my db with <code>airflow initdb</code>.</p>
  
  <p>Then I run <code>airflow webserver -p 8080</code> and it seems running. When I go to <a href="http://0.0.0.0:8080/" rel="noreferrer">http://0.0.0.0:8080/</a> I can't see any user interface. If I try to run again the <code>airflow webserver</code> I got </p>
  
  <p><code>Error: Already running on PID 6244 (or pid file '/home/marcofumagalli/airflow/airflow-webserver.pid' is stale)</code></p>
  
  <p>so i suppose that webserver is running.</p>
  
  <p>Is it something related to proxy?</p>