White page if enable only some page if open via CF Proxies

Dear everybody,

I’m sorry if tagging this topic wrong.
I use cloudflare for 8 years and this is my first time i meet the strange error. If i set host IP Address with real server IP, all pages displayed correctly.
If i remove the IP address from hosts file (connection to domain will proxied via CF) it sent some white pages in some URI.
I tried everything, remove caches on my server and caches on CF via purge cache → custom URL. The problem still happen.
How i can solve it?

Thank you.
Regards.