title: What could be causing epub, mobi and zip files to fail to download on an iPhone running ios 13?
body: <p>I am having problems on my local server when trying to serve files to an iPhone running ios13. The problems only occur with file types that cannot be rendered in the browser, by that I mean files such as epub, mobi and zip that require me to manually click on download. </p>
  
  <p><a href="https://i.stack.imgur.com/g4Dd1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/g4Dd1.png" alt="Manually download file in iOS"></a></p>
  
  <p>Files such as text and pdf have no issue in any browser. </p>
  
  <p>Safari is able to download Mobi, Epub and Zip files, but Chrome, Firefox and Edge all fail giving vague messages like “Couldn’t Download” or “Download Failed”. Try Again.</p>
  
  <p><a href="https://i.stack.imgur.com/Gab3U.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Gab3U.png" alt="Failed mobi download on iPhone in Chrome Mobile Browser"></a></p>
  
  <p>Originally I was serving the files using Nginx, X-Accel-Redirect and PHP, but I found that using a direct url had the same problem. The server is running HTTPS and HTTP2. Mime types are properly configured in Nginx.</p>
  
  <p>In each case, regardless of whether the file was successfully downloaded or not, the access logs showed status code 200.</p>
  
  <p><strong>My questions are:</strong> </p>
  
  <ol>
  <li>What could be causing the failed downloads and how can I fix it?</li>
  <li>What other things should I investigate to shed more light on this
  issue?</li>
  </ol>