After a week (or maybe a little earlier, I didn't check every day) I finally got my certifications. Thank you! But actually the https is broken because of mixed-content, caused by cloudflare.

My page declare css in relative path, like inc/style.css. Via cloudflare it becomes absolute http url, like http://mydomain.com/inc/A.style.css.pagespeed.cf.5Dzr782jVo.....

This won't work in https. You should change it to //, or better yet kept the relative path. Thanks.