Cloudflare 自动把我网站的 SSL/TLS 策略从 flexible 改为 restrict， 导致网站无法访问。

刚刚收到 CF 发的邮件，说自动帮我升级了 SSL/TLS 策略。

From flexible to strict 

Why am I receiving this email, and what are automatic SSL/TLS upgrades? 
Automatic SSL/TLS upgrades are enabled for one or more of your domains. As a result, Cloudflare will see if it can communicate with your origin server over more secure connections and will automatically upgrade them on your behalf if so to improve security. 

按照他的说法，CF 会自动检测是否能够正常连接才会升级，然而现在我的网站 526 了。