Although I have found the solution online, which is to restart the server and purge all.
But I think this may be annoying as I sometimes need to change the url.
For example, when I built that page, the slug is in singular form, I later decided that plural form is better, then I changed the url for that page.
To restart the sever and purge all every time editing the url is too annoying.
Do I need to rewrite the rule or set something in Cyberpanel so that I can avoid this?
Thanks!