Error 522 with AWS Route53

This has been happening for two domains. I use AWS hosted zones for those two domains and enabled cloudflare for it. Initially it works well (maybe for 2 days), and then all in a sudden, the 522 error begin to occur:

“The initial connection between Cloudflare’s network and the origin web server timed out. As a result, the web page can not be displayed”

I can use the public IP provided by aws to access my website directly and without no issues. Could that be aws is blacklisting cloudflare ips after some time?