title: IIS application pool started but API not responding
body: <p>I have two servers running an API, but on one of them the API is not responding anymore. This happened right after my colleague added <em>another</em> API under the same application pool... Since then the API stopped responding and I get a 503 Service Unavailable error, but only on the one server. The other server runs the API without problems.</p>
  <p>This is what I tried:</p>
  <ul>
  <li>I first removed the API my colleague added from application pool and restarted the pool, which didn't work</li>
  <li>Recycling the application pool.</li>
  <li>Rebooting the server.</li>
  <li>Changing the Rapid-Fail Protection setting to false.</li>
  <li>Changing the identity from ApplicationPoolIdentity (which it has always used) to LocalService, LocalSystem, NetworkService and back to ApplicationPoolIdentity.</li>
  <li>Creating a new application pool and moving the API to that one. Stop/start/recycle not working here either.</li>
  </ul>
  <p>The application pool keeps running when I start it and I see no errors in the event viewer. The code on both servers are the same. I tried connecting to the server with telnet and that worked, so there are no network issues.
  I can still access the API throught localhost, but when connecting through the website I get the 503 error.</p>
  <p>Is there anything else I can try?</p>