title: Owin self-host - Failed to listen on prefix 'http://localhost:12345/' because it conflicts with an existing registration on the machine
body: <p>I'm trying to self-host a simple WebAPI:</p>
  
  <pre><code>public class AccountViewApplication {
      protected IDisposable WebApplication;
  
      public void Start() {
          WebApplication = WebApp.Start&lt;WebPipeline&gt;("http://myhost.mymachine.me:12345");
          new AccountViewApplication().Start();
      }
  
      public void Stop() {
          WebApplication.Dispose();
      }
  }
  </code></pre>
  
  <p>The first time I run this, it starts to listen just fine, but the next time that I try - I get this:</p>
  
  <p>Failed to listen on prefix '<a href="http://myhost.mymachine.me:12345/" rel="nofollow noreferrer">http://myhost.mymachine.me:12345/</a>' because it conflicts with an existing registration on the machine</p>
  
  <p>What can I do to make it listen every time, and not complain about an existing reservation? </p>