Fetch HTTPS resources directly
Restricting and Controlling PageSpeed optimization rewriting
By default Google PageSpeed doesn't fetch HTTPS resources. Use FetchHttps to enable it.
Configuration
Enable pagespeed FetchHttps enable
Disable pagespeed FetchHttps disable
Recommendation
Our recommendation is to set up LoadFromFile, if possible (the static files exist on disk), instead of using Fetch HTTPS
Alternative
Alternatively, you can apply MapOriginDomain to map https to http (if plain http is served).