title: Ruby app only works when Passenger is "disabled"
body: <p>I have deployed a Sinatra application on an Ubuntu server using Apache and Passenger. Through some trial and error, I realize the app only works when the passenger module is disabled.</p>
  
  <pre><code>$ a2dismod passenger
  </code></pre>
  
  <p>After an Apache restart, the app runs as expected.</p>
  
  <p>If I re-enable the module...</p>
  
  <pre><code>$ a2enmod passenger
  </code></pre>
  
  <p>...I see this warning upon Apache restart:</p>
  
  <pre><code>[warn] module passenger_module is already loaded, skipping
  </code></pre>
  
  <p>and the app stops working. Apache responds, serving the contents of the vhost's document root, but is not recognized by Passenger.</p>
  
  <p>I'm glad my app works, but I'm not sure how to explain the reversed effect of enabling/disabling the passenger module.</p>