title: pagespeed convert image to webp but use not secure protocol (http)
body: <p><a href="https://i.stack.imgur.com/cNo5q.png" rel="nofollow noreferrer">Chrome Mixed Content Message</a></p>
  
  <p>My site was enabled nginx pagespeed module and all resources are loaded in https but webp url ( created by pagespeed ) is in http. I got a not-secure notice from Chrome brower. How to fix it?</p>
  
  <pre><code>Mixed Content: The page at 'https://interview.tw/c/QHkN' was loaded over HTTPS, but requested an insecure image 'http://assets.interview.tw/images/xmask.jpg.pagespeed.ic.yjlu3AxgW4.webp'. This content should also be served over HTTPS.
  </code></pre>