title: Ngrok errors '502 bad gateway'
body: <p>Quite new to using any sort of Web App stuff, and I've been trying to slowly build a Facebook Messenger Bot. When I try to use ngrok I can't visit the address I'm given, i.e:</p>
  
  <pre><code>ngrok http 5000
  </code></pre>
  
  <p>is what I'm putting in the command line, and it's returning this:</p>
  
  <pre><code>ngrok by @inconshreveable
  
  Session Status                online
  Version                       2.1.18
  Region                        United States (us)
  Web Interface                 http://127.0.0.1:4040
  Forwarding                    http://ea986ca5.ngrok.io -&gt; localhost:5000
  Forwarding                    https://ea986ca5.ngrok.io -&gt; localhost:5000
  
  Connections                   ttl     opn     rt1     rt5     p50     p90
                                0       0       0.00    0.00    0.00    0.00
  </code></pre>
  
  <p>But when I take the address '<a href="https://ea986ca5.ngrok.io" rel="noreferrer">https://ea986ca5.ngrok.io</a>' as is required by the Facebook developer's page, it says:</p>
  
  <pre><code>The connection to http://ea986ca5.ngrok.io was successfully tunneled to your
  ngrok client, but the client failed to establish a connection to the local  
  address localhost:5000.
  
  
  Make sure that a web service is running on localhost:5000 and that it is a 
  valid address.
  
  
  The error encountered was: dial tcp [::1]:5000: connectex: No connection 
  could be made because the target machine actively refused it.
  </code></pre>
  
  <p>Is it a problem with my local port? Thanks!</p>