The cache is on now. Not only the WordPress system can cache the content, but also notify the CDN to purge relative pages when a post is posted, edited ,deleted.

Now the cache time is set to be 5 minutes on the CDN, for the index page and URLs with a ‘.html’ suffix.

Added:

Because of the cache, all visitors can see the same content as what the Admin user can see, if the Admin user happens to visit the page when there’s no cache or the cache has expired, in this case, the CDN will make the Admin user version as the cache.

So i deleted the cache rules of the dynamic content, but the static files(images, .js, .css, etc.) can still get cached.