All sites should be protected with HTTPS. See the Does not use HTTPS post to learn why and how to set up HTTPS on your server.
How the Lighthouse HTTP redirection audit fails
Lighthouse flags pages that aren't redirected to HTTPS:
Lighthouse changes the page's URL to HTTP, loads the page, and then waits for the event from the Chrome Remote Debugging Protocol that indicates that the page is secure. If Lighthouse doesn't receive the event within 10 seconds, the audit fails.
How to redirect HTTP traffic to HTTPS
Once you've set up HTTPS, make sure that all unsecure HTTP traffic to your site is redirected to HTTPS:
- Use canonical links in the head of your HTML page to help search engines figure out the best way to get to the page.
- Configure your server to redirect HTTP traffic to HTTPS. See your server's documentation to figure out the best way to do this.