title: ngrok with visual studio 2017 and IIS express fails to connect
body: <p>So I'm trying to setup my dev machine to be able to respond to some webhooks, as per the twilio documentation here:</p>
  
  <p><a href="https://www.twilio.com/docs/usage/tutorials/how-use-ngrok-windows-and-visual-studio-test-webhooks" rel="noreferrer">https://www.twilio.com/docs/usage/tutorials/how-use-ngrok-windows-and-visual-studio-test-webhooks</a></p>
  
  <p>I've got ngrok installed, and have the tunnel up and running, pointing at the port that is specified in visual studio. In this case, 44336.
  <a href="https://i.stack.imgur.com/55nl0.png" rel="noreferrer"><img src="https://i.stack.imgur.com/55nl0.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/BDXbr.png" rel="noreferrer"><img src="https://i.stack.imgur.com/BDXbr.png" alt="enter image description here"></a></p>
  
  <p>However, if I go to visit the external URL, I get a very long load time, and eventually a 502 error. Visiting localhost works fine as expected.</p>
  
  <p>So, I tried setting ngrok to point at 8080, and I get a little further along, but still no luck with the following error message in the browser.</p>
  
  <p><a href="https://i.stack.imgur.com/yMC3Y.png" rel="noreferrer"><img src="https://i.stack.imgur.com/yMC3Y.png" alt="enter image description here"></a></p>
  
  <p>With the first tunnel attempt, I can see the GET/ requests show up in the ngrok client, but no error. In the second attempt, I can see the 502 errors:</p>
  
  <p><a href="https://i.stack.imgur.com/ZXcRE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ZXcRE.png" alt="enter image description here"></a></p>
  
  <p>So I have two questions: How can I diagnose the source of the problem? And how can I setup IIS to accept connections from ngrok?</p>